Caution: Hullman Post about tubes.
Skip May
A Caution about "Guru Posts"
I drop by the news group here to see what's cooking about twice a week.
There's always the spam nuts, the flakes and the "want to be guru's" in
with the rest of the crowd.
I often see posts from these "want to be guru's" that mistate facts,
information or just plain quote things from textbooks. I've seen two
such posts from Robert Hullman of this type. While I don't want to pick on
him, I'm going to use his as an example of this type of "technoblather".
You then make your own choices about his and all the other free
information on the net, but don't take everything posted as gospel
engineering.
Robert,
First Off:
In your previous post which adds a parallel resistor/diode combination in
the cathode lead to measure current by the voltage drop across the
resistor: What exactly does the diode do in circuit? Would the diode ever
forward bias? What would this mod do to the stabilty and or tone of the
amp? Most of all, what's wrong with this method of measuring bias?
Second:
Regarding your current post, tubes are not "mechanical devices", read the
book. Although a small issue, it's important.
Most of your text reads like you typed in old book theory with common
"technoblather" from the pages of an RCA receiving tube handbook. Most
people know most tubes are made of glass* and small metal parts which
might damage when treated rough. A "no-brainer" of sorts?
Here's some quotation with comments:
[snip]
>For tubes to work, they must be heated hot enough to cook round steak!
Check your temps again Robert, steak cooks at a much lower temp.
[snip]
>Heat is a big problem in tubes ... it is needed to "boil" off
>the electrons from the cathode however, when things get that hot,
>chemical compounds will break down or worse, melt!
Heat is not a problem, in a properly designed and operated amp, heat is
controlled. More technoblather to follow:
[snip]
>Try and keep your amp well ventelated. It
>could mean nothing more than moving your amp away from the wall a few
>more inches to cutting holes in the sides to install fans. Speaking of
"Well ventilated" is from the no-brainer school of thought...
[snip]
>fans, that is probably the best way to keep everything cooler. Find
>some way to direct a fan on to the tubes.
Wrong! Where's does this fact come from Robert? Isn't glass an insulator?
BETTER THAN 50% OF THE TUBE AMP GURU'S HAVE THIS WRONG! Maybe after Robert
has a chance to comment (along with others), I'll provide the facts. I
just want to see if I can nail down some detailed answers from the guru's
before I set the record straight. Just the facts folks... beware of smoke
and mirrors.
On we go...
[snip]
>If the bulb temperature (the temp of the glass envelope) is kept lower,
>the radiated heat from the metal parts will be absorbed better
>and therefore they will run a little cooler and reduce
Absorbed by what Robert?
Kind of off the beaten path here Robert, but a very important clue to the
truth is in the above, can you tell us what it is?
I'll detail this in a followup post here.
A little more technoblather and then a big slip up by Robert:
[snip]
>some of the chemical decomposition. (one other thing regarding
>heat, you should insure that your amp's bias is correct ... an under
>biased amp will just make the tubes unable to dissapate as much
>heat and will reduce their lives. You should get the bias
>check and adjusted every 6 months because
Robert, please explain to the crowd how an underbiased amp is "unable to
dissapate as much heat..." Although this may just be incorretly stated,
the fact is the quanity of "heat" a tubes' plate will dissapate always
remains the same. The typical bias adjustment controls the resting
operating point of the tube(s). An amplifier with incorrect bias, will
exhibit all the "sound bad distortion" you've come to expect, but will not
change is ability to dissapate heat. What element determins how often you
should have your bias checked? What would this change be?
An amplifier with the bias set wrong could have higher idle/operating
current and run hoter within it's ratings , but the amount of power the
tube can handle, remains the same. If the tubes are biased wrong but still
within their ratings, how will tube life be greatly reduced, Robert?
Anyone? Details please? Let's filter the technoblather out.
What's the best way to bias an amp Robert? Anyone?
The reason this type of post needs to be brought to your atttention is
that these unchecked statements are often taken as fact. This should not
happen as the end result is "it will cost you money and time". Question
everyone's advise, even the "guru's" when they post.... even me. Hopefully
the facts will filter themselves out. Often, those who know less will
post here to appear know more.
Last but not least, USE THE EMAIL ADDRESS BELOW MY NAME ONLY! The above
address is only an email drop address and I won't receive your replies.
Hope this gets your motor going...
Cheers
Skipp Mays
reply only to: ma...@indigo.ucdavis.edu
Lord Valve
From: detr...@ix.netcom.com(Lord Valve)
Newsgroups: alt.guitar.amps
Subject: Re: Caution: Hullman Post about tubes.
References: <5rt6td$2m3$1...@mark.ucdavis.edu>
In <5rt6td$2m3$1...@mark.ucdavis.edu> sk...@dilbert.ucdavis.edu (Skip May)
writes:
>
>A Caution about "Guru Posts"
>
>I drop by the news group here to see what's cooking about twice a
week.
>There's always the spam nuts, the flakes and the "want to be guru's"
in
>with the rest of the crowd.
>I often see posts from these "want to be guru's" that mistate facts,
>information or just plain quote things from textbooks. I've seen two
>such posts from Robert Hullman of this type. While I don't want to
pick on
>him, I'm going to use his as an example of this type of
"technoblather".
>
>You then make your own choices about his and all the other free
>information on the net, but don't take everything posted as gospel
>engineering.
LV: Well...I might take a shot at a few of these, since Skippy seems
to have such a hardon about it. Since he's posting from an .edu
domain, chances are rather good that he's one o' those cats who are
long on book-learnin' and short on stage time...and things DO tend to
operate a little differently in the field than they do in the lab...
>
>Robert,
>
>First Off:
>In your previous post which adds a parallel resistor/diode combination
in
>the cathode lead to measure current by the voltage drop across the
>resistor: What exactly does the diode do in circuit?
LV: Nothing.
>Would the diode ever forward bias?
LV: Nope.
>What would this mod do to the stabilty and or tone of the amp?
LV: Nothing. And I wouldn't call putting a 1-ohm resistor in series
with the cathode a 'mod'; it's just a measurement convenience.
>Most of all, what's wrong with this method of measuring bias?
LV: I know what you'd like me to say...that it doesn't take screen
current into account. OK, it doesn't. So what? A couple of milliamps
is negligible...we're not looking for laboratory accuracy or trying to
achieve some absolute value here; we're just looking for the best tone.
The bias point necessary to achieve that tone may fall anywhere within
(or even outside, if lower) the published (or actual) specs for the
tube. As long as you're not crowding the high end of the current spec,
this is a non-issue. Besides, you would tend to err on the LOW side of
the spec, since the screen current would be ADDED to the cathode
current with this method.
LV: Jeez, dude...don't do us any favors...
I
>just want to see if I can nail down some detailed answers from the
guru's
>before I set the record straight. Just the facts folks... beware of
smoke
>and mirrors.
LV: Personally, I like 'em on the hot side. Power tubes are (or
should be) designed to run at the proper temperature WITHOUT additional
cooling, as long as specs are not exceeded. Tubes designed to burn
base-down which are being operated base-up could possibly derive some
slight additional longevity from fan-cooling, but this would be more
beneficial to the plastic base than to the metal parts inside the tube.
As far as the glass goes...if it were pure, it probably wouldn't heat
up much at all. Most of the heat which leaves a tube does so as
infra-red radiation, and it goes through the glass like it wasn't even
there. Only impurities in the glass (and dirt on the surface, which is
why I always hit the tubes with some Windex when I'm doing maintenance)
can absorb this radiation, thus gradually raising the temperature of
the bulb. (Some heat is added by direct conduction where the wires
exit the bulb, too.) Heat from the bulb is re-radiated (at a much
slower rate) at a different frequency of IR. (Lower, I think...)
LV: I reckon that as the cathode degrades over time, we'd want to
lower the bias voltage slightly to suck them trons a leetle bit harder.
This would increase the current back up to the optimal point.
Remember, though...we're lookin' for TONE here, so I'd only adjust the
bias if the musician complains about the way the amp sounds.
>
>An amplifier with the bias set wrong could have higher idle/operating
>current and run hoter within it's ratings , but the amount of power
the
>tube can handle, remains the same. If the tubes are biased wrong but
still
>within their ratings, how will tube life be greatly reduced, Robert?
>Anyone? Details please?
LV: It wouldn't.
Let's filter the technoblather out
>What's the best way to bias an amp Robert? Anyone?
LV: The 'best' way to bias an amp is the one that makes it sound the
way the musician likes it to sound. There are several different
ways...cathode resistor, plate resistor (for you accuracy freaks),
output transformer primary shunt method (scary, and not all meters can
do it), the crossover notch method, the 'by ear' method (which usually
starts out with one of the other methods to get into the ballpark, and
finishes up with some listening/diddling/listening/diddling action),
and the harmonic distortion meter method. I've used 'em ALL at one
time or another. I routinely use the crossover notch method on older
Marshalls; I seem to be able to achieve what my customers want on those
amps with a scope and my eyeballs. For Fenders, I like the cathode
resistor method; many times, I'll finish up by ear, if the customer is
in the shop at the time. (Sometimes, I gotta do my own pickin' and,
well...I, er...play the guitar like you'd imagine an organist would.
Badly!!) Most Ampegs aren't adjustable, so I usually do a transformer
shunt check to make sure things are in the ballpark. A peek at the
quiescent current draw for the entire amp is in order here, also. I
have a snazzy HP harmonic distortion meter, too, but I usually only use
it on high powered SS PA amplifiers...gee-tah pickahs invariably like
more harmonic distortion than the lowest that can be achieved, for some
reason.
>
>The reason this type of post needs to be brought to your atttention is
>that these unchecked statements are often taken as fact. This should
not
>happen as the end result is "it will cost you money and time".
Question
>everyone's advise, even the "guru's" when they post.... even me.
Hopefully
>the facts will filter themselves out. Often, those who know less will
>post here to appear know more.
>
>Last but not least, USE THE EMAIL ADDRESS BELOW MY NAME ONLY! The
above
>address is only an email drop address and I won't receive your
replies.
>
>Hope this gets your motor going...
>
>Cheers
>Skipp Mays
>
>reply only to: ma...@indigo.ucdavis.edu
Lord Valve Speaketh:
Well, Skippy...I've addressed a few of the questions you've raised,
acuurately, I think...but from where I sit, it looks like you're gonna
lay the Big Hotshit Engineer routine on us, so let me just say this in
advance: Everything I've written above is knowledge I've gained from
30 years of field experience. Guitar amps (and my Leslies) are
routinely operated beyond normal parameters, and 'by-the-book'
procedures for testing and adjustment of these devices often does not
produce the results musicians desire. The 'best' methods are the ones
which produce the desired results; often, these methods are at odds
with conventional wisdom. As an aside...I'd be remiss if I didn't
mention that your spelling is atrocious, your syntax is laughable, and
DUDE...if you're gonna diss somebody, at LEAST get his name right!
It's Robert Hull. I mean, if you're gonna come on like you're the Word
and the Light, you could at least take the time to proofread your
stuff, ok?
Lord Valve
jimmycr...@idontcare.com
Scott Hinman
Lord Valve wrote:
> LV: Personally, I like 'em on the hot side. Power tubes are (or
> should be) designed to run at the proper temperature WITHOUT additional
> cooling, as long as specs are not exceeded. Tubes designed to burn
> base-down which are being operated base-up could possibly derive some
> slight additional longevity from fan-cooling, but this would be more
> beneficial to the plastic base than to the metal parts inside the tube.
> As far as the glass goes...if it were pure, it probably wouldn't heat
> up much at all. Most of the heat which leaves a tube does so as
> infra-red radiation, and it goes through the glass like it wasn't even
> there. Only impurities in the glass (and dirt on the surface, which is
> why I always hit the tubes with some Windex when I'm doing maintenance)
> can absorb this radiation, thus gradually raising the temperature of
> the bulb. (Some heat is added by direct conduction where the wires
> exit the bulb, too.) Heat from the bulb is re-radiated (at a much
> slower rate) at a different frequency of IR. (Lower, I think...)
>
Hi, LV
I agree with almost all of what you've said in this post, but your
comments on glass absorption of infrared radiation are a little
misleading. Its true that most glasses are transparent to near
infrared radiation (close to the visible region of the electromagnetic
spectrum), but they are all strong absorbers in the mid infrared.
I'm uncertain what you mean by 'pure' glass, as the term glass denotes
a great variety of amorphous chemical compositions. Even pure SiO2,
though, is a strong infrared absorber. (You've no idea how much I
wish I could have a silica based glass that was transparent to
infrared). You're correct that heated glass emits infrared radiation,
but it does so at the same frequencies that it absorbs infrared.
I'm not trying to be critical here, but I appreciate it when people
correct my misconceptions regarding areas in which I am not an expert,
and I suppose you must, as well. Keep up the good info on amps!
Best regards,
Scott H.
.*°*€°.- Remove the ?'s to reply-.*°*€°.
doovy
Scott Hinman <ashinman@chem.?ucalgary?.ca> wrote:
> Its true that most glasses are transparent to near
>infrared radiation (close to the visible region of the electromagnetic
>spectrum), but they are all strong absorbers in the mid infrared.
>I'm uncertain what you mean by 'pure' glass, as the term glass denotes
>a great variety of amorphous chemical compositions. Even pure SiO2,
>though, is a strong infrared absorber. (You've no idea how much I
>wish I could have a silica based glass that was transparent to
>infrared). You're correct that heated glass emits infrared radiation,
>but it does so at the same frequencies that it absorbs infrared.
I agree...the glass around the tube _must_ be absorbing (and emmiting)
some of the heat (infrared radiation) simply because (as everyone
knows) the glass is very hot while the amp is running. Keeping the
glass cool will allow better heat dissapation, but how much better I
don't know. So, I guess Robert's original idea about having a fan on
the tubes must have some merit. Just my .02 microcents.
remove the usual stuff from "reply to" to reply
Lord Valve
In <5s2jse$n...@ds2.acs.ucalgary.ca> Scott Hinman
<ashinman@chem.?ucalgary?.ca> writes:
>Lord Valve wrote:
>
>> LV: Personally, I like 'em on the hot side. Power tubes are (or
>> should be) designed to run at the proper temperature WITHOUT
additional
>> cooling, as long as specs are not exceeded. Tubes designed to burn
>> base-down which are being operated base-up could possibly derive
some
>> slight additional longevity from fan-cooling, but this would be more
>> beneficial to the plastic base than to the metal parts inside the
tube.
>> As far as the glass goes...if it were pure, it probably wouldn't
heat
>> up much at all. Most of the heat which leaves a tube does so as
>> infra-red radiation, and it goes through the glass like it wasn't
even
>> there. Only impurities in the glass (and dirt on the surface, which
is
>> why I always hit the tubes with some Windex when I'm doing
maintenance)
>> can absorb this radiation, thus gradually raising the temperature of
>> the bulb. (Some heat is added by direct conduction where the wires
>> exit the bulb, too.) Heat from the bulb is re-radiated (at a much
>> slower rate) at a different frequency of IR. (Lower, I think...)
>>
>I agree with almost all of what you've said in this post, but your
>comments on glass absorption of infrared radiation are a little
>infrared radiation (close to the visible region of the electromagnetic
>spectrum), but they are all strong absorbers in the mid infrared.
process which allows the most heat to leave the tube would be dependent
on the wavelength in question, then...right? Either direct radiation
through the glass at near IR or absorption/re-radiation at the mid IR
freqs?
>I'm uncertain what you mean by 'pure' glass, as the term glass denotes
>a great variety of amorphous chemical compositions. Even pure SiO2,
>though, is a strong infrared absorber. (You've no idea how much I
>wish I could have a silica based glass that was transparent to
>infrared).
LV: Yeah, I shoulda thought about that before I wrote it...there are
probably a jillion different kinds of glass. I wonder if those
red-tinted or sky-blue EL34s are better or worse at passing IR than
regular 'clear' ones are. Doesn't a greenhouse work by passing IR of
one wavelength (from sunshine), but not allowing IR of a different
wavelength (re-radiated by the stuff inside) to leave? I wonder if
this has any bearing on heat received from nearby tubes.
You're correct that heated glass emits infrared radiation,
>but it does so at the same frequencies that it absorbs infrared.
>I'm not trying to be critical here, but I appreciate it when people
>correct my misconceptions regarding areas in which I am not an expert,
>and I suppose you must, as well. Keep up the good info on amps!
>Best regards,
> Scott H.
>
> .*°*€°.- Remove the ?'s to reply-.*°*€°.
LV: Thanks for the lesson in materials science, Scott...contrary to
popular opinion, I don't know EVERYTHING...just damn near. :)
Lord Valve
ou...@hottubes.com
Ned Carlson
In article <5rutou$f...@sjx-ixn6.ix.netcom.com>,
detr...@ix.netcom.com(Lord Valve) wrote:
> LV: Well...I might take a shot at a few of these, since Skippy seems
> to have such a hardon about it. Since he's posting from an .edu
> domain, chances are rather good that he's one o' those cats who are
> long on book-learnin' and short on stage time...and things DO tend to
> operate a little differently in the field than they do in the lab...
Well, LV, turns out you & I are winding up on the same side of the line
more often than not. As I've noted on RAT: lotsa book learnin' & little
experience sometimes= very silly Usenet postings. Funny thing is some of
the most thought provoking questions I've had were from 17 year old kids.
So if anyone reading this is a tube amp newbie, don't let it get you
down..just don't hop off flaming folks at the start...
I tend to think EE's are best after being cooked for, say,
20 years or so by management, QC, factory floor personnel
and endusers. Just MHO. Interesting anecdotes available
on request.
BTW, UC Davis is one of the major centers of research
about kewl stuff like vacuum tube IC chips that run at
a terahertz. Little to do with the tone of Twin Reverbs,(yet!)
but interesting nonetheless...see da mindblowin' details at
http://www.triodeel.com./area51.htm
-------------------==== Posted via Deja News ====-----------------------
http://www.dejanews.com/ Search, Read, Post to Usenet
mark.a...@guidant.com
> Well, LV, turns out you & I are winding up on the same side of the line
> more often than not.
>
> I tend to think EE's are best after being cooked for, say,
> 20 years or so by management, QC, factory floor personnel
> and endusers. Just MHO. Interesting anecdotes available
> on request.
As a EE (Elect. Engr.), I also like watching my fellow
professionals get flamed for taking the wrong side on an
issue. We all make mistakes, but it is better to say
nothing or "I don't know" than to trot out the credentials
and try bluff your way with technical B.S.
Most of my peers graduating from EE school 15 years
back were experts in 5 volt power supplies and TTL chips.
A lot of them couldn't bias a BJT much less a tube or a FET.
I felt my path in the RF sub-speciality lifted the veil of the
EE black art and put everything into perspective.
My current favorite motto: "Everything is an antenna, it's just
that some things make better antennas."
Mark Amundson,
Ned Carlson
mark.a...@guidant.com wrote:
>
>As a EE (Elect. Engr.), I also like watching my fellow
>professionals get flamed for taking the wrong side on an
>issue. We all make mistakes, but it is better to say
>nothing or "I don't know" than to trot out the credentials
>and try bluff your way with technical B.S.
In a way, I think me *not* having much in the way of
credentials is a benefit, I can't get in a diploma-waving
flamefest.
BTW, I have lotsa friends & customers who are EE's and most
don't mind having thier profession's nose tweaked a bit
once in a while, fortunately for me, Mark, you fall in
that category!
>A lot of them couldn't bias a BJT much less a tube or a FET.
I get questions all the time from EE's about tubes, much of the
questions are about tube ratings, which are confusing to
many folks as often there's things one can do with a tubes
that you can't do with a transistor..example, did you know there's
published (but not widely circulated since it's an odd application)
ratings for using 6550 as a shunt reg at 3 kilovolts?
6HB5's with 770V ratings get used as direct drive electrostaic
(hmm, anyone ever play a geetah through an Acoustat?)
speaker amp at something like 3KV, too.
Back to the subject at hand, the military did a study on using
heat-disspating tube shields, and indeed they do extend
tube life. But rock n' roll ain't rocket science, and we're not
talking OTH radars in Stealth fighters, if a geetah pickah
think his tone's better with hot tubes, and if he's willing to carry
a spare pair around and spend a few extra bucks to retube
his amp more often, I say : wail away.
If he likes the sound of cooler tubes better,I'd say
try some Pearl Tube Coolers.
Ned Carlson, Triode Electronics, Chicago, IL http://www.triodeel.com
Open 12:30-8 PM CT, 12:30-5 PM CT Sat Closed Wed
ph:773-871-7459 fax 773-871-7938 "where da tubes are"
Email catalogs: email our CataBot: cat...@triodeel.com
Jeff Vineburg
>BTW, UC Davis is one of the major centers of research
>about kewl stuff like vacuum tube IC chips that run at
more importantly, Davis is also the home of Woodstock's Pizza - the
world's greatest.
(just went there on vacation)
--------------------------------------------------------------
Jeff Vineburg !je...@op.net! Nuclear Fish !nuke...@netaxs.com!
http://www.op.net/~jeffv http://www.netaxs.com/~nukefish
lefty guitar info, musical humor song parodies, as heard on Stern show
Joe Cocker Spaniel's page
Ned Carlson
nos...@my.house (Jeff Vineburg) wrote:
>more importantly, Davis is also the home of Woodstock's Pizza - the
>world's greatest.
Ever been to Chicago, or Brooklyn?
If you've been to either place and done ate pizza,
I'll *possibly* respect your opinion.
Lee MacMillan
Ned Carlson wrote:
>
> nos...@my.house (Jeff Vineburg) wrote:
>
> >more importantly, Davis is also the home of Woodstock's Pizza - the
> >world's greatest.
>
> Ever been to Chicago, or Brooklyn?
>
> If you've been to either place and done ate pizza,
> I'll *possibly* respect your opinion.
>
mom & pop pizzeria to the over-hyped Gino's East. But even my wife
("there's nothing like Brooklyn pizza") loves Papa Del's.
Lee
--
Indiana's best equipped hack guitar player.
Remove the $ to reply.
Skip
Earlier this week I posted a Caution to the newsgroup about guru posts
and the possible errors they make. While not wanting to get into anyones
face directly, I chose a "guru" type post from Mr Hull to use as an
example. I also asked for additional comments from the ranks and emailed
Mr Hull that I placed my post using his article and that he should look
at it and comment back if he cared to.
Well Mr Lord Valve couldn't pass this one up and dove in with both feet.
So let's have a look at what "Mr Valve says" and maybe stir up more
conversation, shall we.
Please refer the the previous post if you want to read the exact posts
as they originally were made.
> >A Caution about "Guru Posts"
> >I drop by the news group here to see what's cooking about twice a
> week.
> >There's always the spam nuts, the flakes and the "want to be guru's"
> in
> >with the rest of the crowd.
> >I often see posts from these "want to be guru's" that mistate facts,
> >information or just plain quote things from textbooks. I've seen two
> >such posts from Robert Hullman of this type. While I don't want to
> pick on
> >him, I'm going to use his as an example of this type of
> "technoblather".
> >
> >You then make your own choices about his and all the other free
> >information on the net, but don't take everything posted as gospel
> >engineering.
> LV: Well...I might take a shot at a few of these, since Skippy seems
> to have such a hardon about it. Since he's posting from an .edu
> domain, chances are rather good that he's one o' those cats who are
> long on book-learnin' and short on stage time...and things DO tend to
> operate a little differently in the field than they do in the lab...
First off, when you see or hear someone attack something that has
nothing to do with the topic, this is usually a diversion ploy. Lord
Valve, my domain has nothing to do with my education, job, experience
level or the facts at hand. It does indicate a possible lack of self
esteem or confidence on your part.
[snip]
> >
> >Robert,
> >
> >First Off:
> >In your previous post which adds a parallel resistor/diode combination
> in
> >the cathode lead to measure current by the voltage drop across the
> >resistor: What exactly does the diode do in circuit?
> LV: Nothing.
>
LV is right, it does waste about 19 cents for a good diode.
> >Would the diode ever forward bias?
> LV: Nope.
Pretty much, diodes are sometimes used to prevent certain component
damage when big meltdowns occur.
>
> >What would this mod do to the stabilty and or tone of the amp?
> LV: Nothing. And I wouldn't call putting a 1-ohm resistor in series
> with the cathode a 'mod'; it's just a measurement convenience.
>
Wrong LV, when Leo Fender sold Fender to CBS, the engineers were allowed
to place these type of mods in the amps to "tame them down", or make
them more reliable. This is usually refered to as the black face to
silver/white face era. Ask any vintage dealer which amp is worth more.
Also tell us how the bias was set at the factory...? Although this mod
is a simple one, I wouldn't want it in my amplifier. Carbon resistors
change value with age, metal film resistors have reactance even at low
values. Be your own judge folks...
> >Most of all, what's wrong with this method of measuring bias?
> LV: I know what you'd like me to say...that it doesn't take screen
> current into account. OK, it doesn't. So what? A couple of milliamps
> is negligible...we're not looking for laboratory accuracy or trying to
> achieve some absolute value here; we're just looking for the best tone.
> The bias point necessary to achieve that tone may fall anywhere within
> (or even outside, if lower) the published (or actual) specs for the
> tube. As long as you're not crowding the high end of the current spec,
> this is a non-issue. Besides, you would tend to err on the LOW side of
> the spec, since the screen current would be ADDED to the cathode
> current with this method.
>
Here we go with foot in mouth again for LV. Explain to me LV where the
path for this screen current goes if not through the cathode? You way
off base here. The cathode contains the sum of the grids and the anode.
Only in higher power radio transmitting tubes are you likely to see any
reverse screen current which doesn't apply here at all.
Your last line about "added to the cathode current" may be your only way
to explain your way out of this one... please do so.
I didn't see you offer any hints here LV, care to comment before my
followup post about this area...?
> I
> >just want to see if I can nail down some detailed answers from the
> guru's
> >before I set the record straight. Just the facts folks... beware of
> smoke
> >and mirrors.
> LV: Personally, I like 'em on the hot side. Power tubes are (or
> should be) designed to run at the proper temperature WITHOUT additional
> cooling, as long as specs are not exceeded. Tubes designed to burn
> base-down which are being operated base-up could possibly derive some
> slight additional longevity from fan-cooling, but this would be more
> beneficial to the plastic base than to the metal parts inside the tube.
There are other factors which come into play here LV. All tubes derive
benefits by cooling of the base and external anode metal pins. Air
movement around the glass is fine, but no where near as effective as air
flowing around the metal pins. This would be a great place to establish
this fact. Have a look at large tube applications. The chassis is
pressurized for air circulation past the tube base pins and external
anode cap if used. Although not practical for some pre-made audio
applications, a new amp design with air moving past the tube base and
base pins would greatly extend the tube life. There are tube sockets
made to take advantage of this method. A quick blurb also to mention
that the tube heater voltage should never be more than the recomended
value unless your looking for a huge reduction in the remaining tube
life. See the Eimac data sheets for tube life vs fill voltage
information.
> As far as the glass goes...if it were pure, it probably wouldn't heat
> up much at all. Most of the heat which leaves a tube does so as
> infra-red radiation, and it goes through the glass like it wasn't even
> there. Only impurities in the glass (and dirt on the surface, which is
> why I always hit the tubes with some Windex when I'm doing maintenance)
> can absorb this radiation, thus gradually raising the temperature of
> the bulb. (Some heat is added by direct conduction where the wires
> exit the bulb, too.) Heat from the bulb is re-radiated (at a much
> slower rate) at a different frequency of IR. (Lower, I think...)
Well, you got your foot in your mouth again over the above, but the
addtional posts set your straight. All you others should go back to the
original thread to read the information others followed up with. It's on
the money...
>
> >On we go...
> >
> >[snip]
> >>If the bulb temperature (the temp of the glass envelope) is kept
> lower,
> >>the radiated heat from the metal parts will be absorbed better
> >>and therefore they will run a little cooler and reduce
> >
> >Absorbed by what Robert?
> >Kind of off the beaten path here Robert, but a very important clue to
> the
> >truth is in the above, can you tell us what it is?
> >I'll detail this in a followup post here.
> >
The cat's out of the bag now, please see my paragraph above about air
movement past the base pins.
> >A little more technoblather and then a big slip up by Robert:
> >[snip]
> >>some of the chemical decomposition. (one other thing regarding
> >>heat, you should insure that your amp's bias is correct ... an under
> >>biased amp will just make the tubes unable to dissapate as much
> >>heat and will reduce their lives. You should get the bias
> >>check and adjusted every 6 months because
> >
> >Robert, please explain to the crowd how an underbiased amp is "unable
> to
> >dissapate as much heat..." Although this may just be incorretly
> stated,
> >the fact is the quanity of "heat" a tubes' plate will dissapate always
> >remains the same. The typical bias adjustment controls the resting
> >operating point of the tube(s). An amplifier with incorrect bias, will
> >exhibit all the "sound bad distortion" you've come to expect, but will
> not
> >change is ability to dissapate heat. What element determins how often
> you
> >should have your bias checked? What would this change be?
> LV: I reckon that as the cathode degrades over time, we'd want to
> lower the bias voltage slightly to suck them trons a leetle bit harder.
> This would increase the current back up to the optimal point.
> Remember, though...we're lookin' for TONE here, so I'd only adjust the
> bias if the musician complains about the way the amp sounds.
> >
You might do this LV, I wouldn't. Have you ever measured the distortion
that occurs when you move the bias to a non linear portion of the
operating curve? The only real fix is to replace an old tube or increase
the heater voltage (with the coresponding decrease in lifespan), not
practical in most amplifiers but often done in higher power tube
equipment. Leave the bias set in the linear operating area where it
belongs.
> >An amplifier with the bias set wrong could have higher idle/operating
> >current and run hoter within it's ratings , but the amount of power
> the
> >tube can handle, remains the same. If the tubes are biased wrong but
> still
> >within their ratings, how will tube life be greatly reduced, Robert?
> >Anyone? Details please?
> LV: It wouldn't.
>
Well, he got this one right...
> Let's filter the technoblather out
> >What's the best way to bias an amp Robert? Anyone?
> LV: The 'best' way to bias an amp is the one that makes it sound the
> way the musician likes it to sound. There are several different
Even if it's not right, keeps the customer comming back. Right or wrong
that seems to be the way of life...
> ways...cathode resistor, plate resistor (for you accuracy freaks),
> output transformer primary shunt method (scary, and not all meters can
> do it), the crossover notch method, the 'by ear' method (which usually
> starts out with one of the other methods to get into the ballpark, and
> finishes up with some listening/diddling/listening/diddling action),
> and the harmonic distortion meter method. I've used 'em ALL at one
> time or another. I routinely use the crossover notch method on older
> Marshalls; I seem to be able to achieve what my customers want on those
> amps with a scope and my eyeballs.
Not much information here, just bragging. But setting an amp is a
compromise. I always use a scope and a meter. I've never seen a perfect
amp but the scope will help me get it to the best place it's gonna be.
For Fenders, I like the cathode
> resistor method; many times, I'll finish up by ear, if the customer is
> in the shop at the time. (Sometimes, I gotta do my own pickin' and,
> well...I, er...play the guitar like you'd imagine an organist would.
> Badly!!) Most Ampegs aren't adjustable, so I usually do a transformer
> shunt check to make sure things are in the ballpark. A peek at the
> quiescent current draw for the entire amp is in order here, also. I
Buzz words, I don't like transformer shunt checks. They tend to place a
strain on older transformers. I've seen two go away in a guys shop
during a shunt test.
> have a snazzy HP harmonic distortion meter, too, but I usually only use
> it on high powered SS PA amplifiers...gee-tah pickahs invariably like
> more harmonic distortion than the lowest that can be achieved, for some
> reason.
It's that what overdriving tube amps are about?
> >
> >The reason this type of post needs to be brought to your atttention is
> >that these unchecked statements are often taken as fact. This should
> not
> >happen as the end result is "it will cost you money and time".
> Question
> >everyone's advise, even the "guru's" when they post.... even me.
> Hopefully
> >the facts will filter themselves out. Often, those who know less will
> >post here to appear know more.
> >
> >Last but not least, USE THE EMAIL ADDRESS BELOW MY NAME ONLY! The
> above
> >address is only an email drop address and I won't receive your
> replies.
> >
> >Hope this gets your motor going...
> >
> >Cheers
> >Skipp Mays
> >
> >reply only to: ma...@indigo.ucdavis.edu
>
> Lord Valve Speaketh:
> Well, Skippy...I've addressed a few of the questions you've raised,
> acuurately, I think...
Not really, please try again... your attack on my domain makes no sense
also.
>but from where I sit, it looks like you're gonna
> lay the Big Hotshit Engineer routine on us, so let me just say this in
> advance:
Is the word used anywhere with my name LV?
> Everything I've written above is knowledge I've gained from
> 30 years of field experience.
I've known people who have been wrong about various things for many more
than 30 years. Look at a lot of organized religons, a thick slice of
bologna for many. By the looks of your above statements, you've been
wrong about a few things for some time.
More bragging and technoblather to follow...
> Guitar amps (and my Leslies) are
> routinely operated beyond normal parameters, and 'by-the-book'
> procedures for testing and adjustment of these devices often does not
> produce the results musicians desire. The 'best' methods are the ones
> which produce the desired results; often, these methods are at odds
> with conventional wisdom.
> As an aside...I'd be remiss if I didn't
> mention that your spelling is atrocious, your syntax is laughable, and
> DUDE...if you're gonna diss somebody, at LEAST get his name right!
I didn't notice you with a teaching degree LV? Feel free to point the
facts out. I don't use a spell check program. I know what Roberts
correct name is, in addition to the fact that I emailed him to look and
comment at my posts. I have nothing to hide or sell on the newsgroup.
You may have nothing to hide, but your always trying to sell us
something.
Again people, try to wade through all this. Even self proclaimed guru
types like LV make mistakes, we all are human. Just hold on to your
pocket book as most of them are trying to sell you something. There are
many things which we will never agree on, but a friendly debate is
always good to get things out in the open.
Cheers, feel free to post onto here or email me direct. Since my edu
domain gets LV and other people excited, please reply to my other
address.
Skipp
Bye...
Quadreverb
I don't have time to give our budy LV a hand with this whole thing, so
I'll just go over one or two points. Skip, you have no idea what you are
talking about when it comes to the cathode resistor bias method. All LV
was saying was that the EXTRA current drawn by the screen grid is
negligable when biasing guitar amps. So the reading you are getting on the
meter is going to be slightly higher than what you are actually getting on
the plate. You just use the number on the meter as a guideline. It's
still coming through the cathode, you dumbass! Why use this method? So you
don't fry your ass on the high voltage on the plates!
The diode in parallel is actually to keep the resistor from blowing. I
think it doesn't turn on until 60 ma or so, so it affects nothing in the
normal bias range we are using in guitar amps. If the current goes higher
than 60 ma, the diode takes the load off the resistor and keeps it from
blowing. This seems like an expensive way to save a $.29 resistor. The 1
ohm doesn't affect guitar amp operation at all.
The resistor added to the cathode you mention in silverface amps has
NOTHING to do with the cathode resistor bias method. If you don't know
this, then you are not worthy to post here dissing LV. Go back to the rock
in which you came.
Your .edu domain name obviously means that you are a janitor or
trenchdigger or whatever at that school you work for. Usually a student or
faculty will check their facts before posting crap.
I can't wait to hear LV respond to this, this is going to be funny for the
rest of us.
Andy
Scott Hinman
Skip wrote:
<snip>
> >LV wrote: As far as the glass goes...if it were pure, it probably wouldn't heat
> > up much at all. Most of the heat which leaves a tube does so as
> > infra-red radiation, and it goes through the glass like it wasn't even
> > there. Only impurities in the glass (and dirt on the surface, which is
> > why I always hit the tubes with some Windex when I'm doing maintenance)
> > can absorb this radiation, thus gradually raising the temperature of
> > the bulb. (Some heat is added by direct conduction where the wires
> > exit the bulb, too.) Heat from the bulb is re-radiated (at a much
> > slower rate) at a different frequency of IR. (Lower, I think...)
>
> Well, you got your foot in your mouth again over the above, but the
> addtional posts set your straight. All you others should go back to the
> original thread to read the information others followed up with. It's on
> the money...
> >
Seeing as one of those other posts you seem to be referring to is mine,
I'll comment here. I certainly was not trying to set LV straight.
I would never presume to do that. His knowledge re tube amps is
well established. I simply stated that I thought his comments on infrared
transmission through glass were misleading. LV is correct that a lot of
heat is lost as infrared radiation. I had intended to point out only
that glass is transparent in the near infrared, and not in the mid infrared.
Since LV fixes amps, and doesn't do infrared spectroscopy, I wouldn't have
expected him to be aware of the distinction. (You're not an infrared
spectroscopist, are you LV?). Your reply to LV makes me wonder if you
really took time to read his post before you started trolling for more
flames. You have read stuff into his reply about the cathode resistor
bias method that he never implied. As for your comments about CBS putting
cathode resistors into SF amps, they didn't put one-ohm resistors in
there, they used 150 ohms. Even then the sonic differences were incurred
not by the use of the cathode resistors, but by their failure to bypass
these resistors with adequate capacitance. (Yes, I have AB'd this).
Also, those resistors were only used in 1968 and 1969 productions. If
you think a one-ohm cathode resistor is going to affect the sound of your
amp, then I think you've never tried it. Please, Skip, usenet doesn't
need any more people trolling for flames. (I'd have no problem with either
LV or Robert Hull working on my amp. You, I don't know about. If you think
*they* are trying to set themselves up as self-appointed gurus, what are
*you* trying to do? They've both posted lots of useful info here, and I
don't recall seeing any from you. Sorry, I don't usually rant like this).
Scott (I hate flame wars) H.
Teleologist
Skip <nos...@thistime.thanks> wrote in article
<33E980...@thistime.thanks>...
> Earlier this week I posted a Caution to the newsgroup about guru posts
> and the possible errors they make. While not wanting to get into anyones
> face directly, I chose a "guru" type post
[snip, snip, and more snip]
What is this, the Spanish Inquisition??? Most people here are quite smart
enough to sift through the good & the bad. In your own case, rather than
exhibit practical knowledge about guitar amps, you seem more intent on
criticizing others in order to prove how much you think you know. If you've
got something to say, say it, not this snively "I know the answer but I'll
wait until everyone else gets it wrong" BS. I know 7 year olds who are more
mature than that & it does absolutely nothing for your credibility.
James Andrews
Jeremy Epstein (7066...@compuserve.com) wrote:
<snip about New Haven pizzerias>
: block but makes a worldclass pie nonetheless. And they spell it the old
: way, "apizza," which I kinda like.
Are you sure that isn't just a misspelling, like "Heresa your apizza,
goomba?" or some other Italian stereotype?
: I will leave the relative rankings of these four New Haven pizzerias as
: an exercise for the reader - there is a lot to be said for each of them.
: As an aside, Tony & Lucille's, also in the same area, makes a mean
: calzone.
On a similar semi-pizza-related note, this place in Fairless Hills PA
makes a thing called... something, I forget. It's basically a deep-fried
calzone. You get this puffed up fried dough, and when you open it at the
bottom is a steaming pool of melted cheese and sauce and toppings....
It's really to die for. Well, literally--as if eating that much cheese
wasn't bad enough for you, they deep fry it. Geez....
Jas.
----------------------
James Andrews
Philadelphia, PA
Remove the X's to reply
Gary Carangelo
There are a lot of various technical aspects regarding guitar amplifier
design, speaker design, speaker baffles, speaker cabinet design, amp and
speaker interaction, combo amp design, etc., etc., etc.
Skip, you've really overdone it with this crybaby (not the wah-wah) post.
A lot of points are opinion and insignificant. If I think I have a
killer amp sound, and someone else thinks it runs too hot, or is not
biased to the microamp, WHO GIVES A FUCK! I'm sure that the perfect
design from a 'cost is not object' point of view will not have killer
tone in many a musicians' eye. Everyone knows that personal preference
and sonic perception reign over any answered questions regardless of how
technical. I don't know LV and I could care a rat's ass if he's the
absolute all-knowing God of tube amp design. But I do know that he
pretty much takes the stance of "This is my opinion, not absolute law".
Hence, my final determination is that you are anal and should get a life.
GC
Thomas C. Clancy
>I'll just go over one or two points. Skip, you have no idea what you are
>talking about when it comes to the cathode resistor bias method. All LV
>
>trenchdigger or whatever at that school you work for. Usually a student or
>faculty will check their facts before posting crap.
That's really kind of an insult to trenchdiggers don't you think?
In fact, I once knew a former trenchdigger who argued with his
chemistry professor over a point about electrochemistry.
I got involved, and told the prof he was wrong. (He basically
was saying that batteries in series don't sum voltage but
batteries in parallel do. The trenchdigger knew this because
there were batteries in his earthmoving equipment, so he said.)
So I'm talking to the prof about
this and he gets out a chemistry book and shows me where it
says this. The book does say make such an erroneous statement.
So then he gets a 2nd book which contradicts the 1st, and then
a 3rd which agrees with the 2nd and contradicts the 1st.
And then, with a thick middle eastern accent the prof starts cussing
the author of the 1st book. "That sonofa bitch! That dirty
sonofabitch!"
spam"@mci2000.com Brian Keith Emerson Fittapaldi
I couldn't agree more with Quadraverb. There is nit-picking and there is
flat-out missing the point and Skippy is at least guilty of the later. I
think LV nailed it when he said "chances are rather good that he's one o'
those cats who are long on book-learnin' and short on stage time...". It
would appear that Ol' Skippy is positioning himself as a Guru. No
thanks...
-beale
Skip May
:
: In fact, I once knew a former trenchdigger who argued with his
: chemistry professor over a point about electrochemistry.
: I got involved, and told the prof he was wrong. (He basically
: was saying that batteries in series don't sum voltage but
: batteries in parallel do. The trenchdigger knew this because
: there were batteries in his earthmoving equipment, so he said.)
:
: So I'm talking to the prof about
: this and he gets out a chemistry book and shows me where it
: says this. The book does say make such an erroneous statement.
: So then he gets a 2nd book which contradicts the 1st, and then
: a 3rd which agrees with the 2nd and contradicts the 1st.
:
: And then, with a thick middle eastern accent the prof starts cussing
: the author of the 1st book. "That sonofa bitch! That dirty
: sonofabitch!"
:
I love it...
skip
everette eglin
>
>[snip, snip, and more snip]
>
>What is this, the Spanish Inquisition??? Most people here are quite
smart
>enough to sift through the good & the bad. In your own case, rather
than
>exhibit practical knowledge about guitar amps,you seem more intent on
>criticizing others in order to prove how much you think you know. If
you've
>got something to say, say it, not this snively "I know the answer but
I'll
>wait until everyone else gets it wrong" BS. I know 7 year olds who are
more
>mature than that & it does absolutely nothing for your credibility.
>
>
While I agree that this is a fair assessment of Mr. May's post, it also
seems clear that this attitude is pervasive on a.g.a. The problem here
is that EVERYBODY posts with an attitude, and that not only makes it
difficult for neophytes to gain information, but also tends to
discourage other very knowledgable people from participating in the
discussion.It is also true, as Mr. May points out, that to many people
post "definitive" answers that deserve great scrutiny. If you'd like to
see how this plays out, let me save you some time.
1.WAM responds changing Skip May's name and header into something
really funny, talks semantics involving Mr. May's response, notes his
vast repair experience, and signs off with a wacky, erzatz email
address.
2. Skip May uses that post to "prove that he was right" and "guru's
can't be trusted", complains about WAM's unacceptable deportment,
implies that he in fact has more experience(and actual book learning),
whines further, but in a philosophical way, poses more questions to the
group, issues an additional warning about "gurus".
3.WAM responds with some finer points regarding grammer, spelling,
etc., spews profanely about the overeducated, recalls his life in the
military, twists Mr. May's name even more absurdly, suggests he has
vanquished another foe, and, finally, draws a butt with various
punctuation marks.
4. We all chuckle
E H E
Skip May
Quadreverb (quadr...@aol.com) wrote:
: I don't have time to give our budy LV a hand with this whole thing, so
: I'll just go over one or two points. Skip, you have no idea what you are
: talking about when it comes to the cathode resistor bias method. All LV
: negligable when biasing guitar amps.
Well, then Andy... we have a hand from the audience with more dis-
information.
You might take a moment to re-read the earlier posts and LV's responce. I
also followed up with an oportunity for others to comment. LV's reply is
not clear although I gave him leave to repost his final version of how and
where the screen current goes. I don't see anything good you have to
offer except some bad language which makes you look real bad.
> So the reading you are getting on the
: meter is going to be slightly higher than what you are actually getting on
: the plate. You just use the number on the meter as a guideline. It's
: still coming through the cathode, you dumbass! Why use this method? So you
: don't fry your ass on the high voltage on the plates!
:
I haven't seen to many guitar amps with High Voltage above 1KV. My fluke
meter easily goes up to 1kv. Any tech should trust his skill and test
equipment or he/she should be inside an amp in the first place.
: The diode in parallel is actually to keep the resistor from blowing. I
: think it doesn't turn on until 60 ma or so, so it affects nothing in the
: normal bias range we are using in guitar amps. If the current goes higher
: than 60 ma, the diode takes the load off the resistor and keeps it from
: blowing. This seems like an expensive way to save a $.29 resistor. The 1
: ohm doesn't affect guitar amp operation at all.
:
Well, well Mr LV lapdog. The above mistake pretty much sums it up for
your technical knowledge. Go back and read the reply from LV as he did get
this one right. I also gave him credit for doing so...
[more technoblather to follow]
: The resistor added to the cathode you mention in silverface amps has
: NOTHING to do with the cathode resistor bias method. If you don't know
: this, then you are not worthy to post here dissing LV. Go back to the rock
: in which you came.
:
: Your .edu domain name obviously means that you are a janitor or
: trenchdigger or whatever at that school you work for. Usually a student or
: faculty will check their facts before posting crap.
:
Again folks, when the going gets tough for the weak minded, they'll
usually attack off topic. I wish I was paid the $16.70 the local trench
digger makes out here...
: I can't wait to hear LV respond to this, this is going to be funny for the
: rest of us.
:
You'll be waiting a long time to hear it Andy, try reading it first.
: Andy
Folks, my intent is not to pick on LV or Andy, only to make you aware that
Lord, god and guru types should never be taken as fact. Please refer to
the earlier posts, make your own mind up. It's much easier to get in line
that stand out.
Cheers
Skipp
please reply by posting or email to: nosp...@juno.com
Skip May
Big word left out by mistake, it should read as:
: :
: I haven't seen to many guitar amps with High Voltage above 1KV. My fluke
: meter easily goes up to 1kv. Any tech should trust his skill and test
: equipment or he/she should NOT be inside an amp in the first place.
:
Skip May
Gary Carangelo (GARYCA...@POSTOFFICE.WORLDNET.ATT.NET) wrote:
: There are a lot of various technical aspects regarding guitar amplifier
: speaker interaction, combo amp design, etc., etc., etc.
This is true Gary, it's often a "season to taste" type of issue for each
person. Isn't this a forum to bring these things to light? Each one of the
above is a science unto itself. That's why wrong information should also
be brought into question.
:
: Skip, you've really overdone it with this crybaby (not the wah-wah) post.
: A lot of points are opinion and insignificant.
Gary, would you care to be more specific? Athough some of the facts are
minor, they are not my opinion. Do the homework Gary or stay in the dark.
: If I think I have a
: killer amp sound, and someone else thinks it runs too hot, or is not
: biased to the microamp, WHO GIVES A FUCK!
Again some bad language which does nothing but make you look bad. I don't
recall any post telling you how to set or run your amp. If someone tells
you to add needless parts to your amp are you going to do it?
I'm sure that the perfect
: design from a 'cost is not object' point of view will not have killer
: tone in many a musicians' eye. Everyone knows that personal preference
: and sonic perception reign over any answered questions regardless of how
... maybe not perfect Gary, but a good amplifier design can be operated
without adding parts you don't need.
: technical. I don't know LV and I could care a rat's ass if he's the
: absolute all-knowing God of tube amp design. But I do know that he
: pretty much takes the stance of "This is my opinion, not absolute law".
:
Gary, go back and read the posts again, you may find you missed a few
things. LV's labels may say opinion and or fact, but we're trying to do
away with the smoke and mirrors here.
: Hence, my final determination is that you are anal and should get a life.:
: GC
:
Thanks Gary, your devotion to lapdog status is noteworthy.
Just the facts please, see if you can keep the off topic attacks to a dull
roar.
Cheers
Skipp
reply by post or email to: nosp...@juno.com
TimTube
In article <33E980...@thistime.thanks>, Skip <nos...@thistime.thanks>
writes:
>
>> LV: The 'best' way to bias an amp is the one that makes it sound the
>> way the musician likes it to sound. There are several different
>
>Even if it's not right, keeps the customer comming back. Right or wrong
>that seems to be the way of life...
Out of all of the spewing BS in this post, I found the above snippet to be
the most annoying.
It is only "right" when the musician/customer likes it. Some like 'em
hotter than others. The ideal way for me is much like LV's, dial it in to
a known good value, play it, or better yet, let the owner play it at
playing condition volumes readjust, up or down to find the "sweet" spot.
Then remeasure to make sure they are not running too hot. If they are
running a little high, say 40-45 for a 450V Fender 6L6 amp, dim the lights
and make sure the plates aren't red, then let the owner decide if the
wants to sacrifice tone for tube life. I've set amps for owners this way
with settings from 20 to 45 ma. There are many factors to consider, the
output of the guitar, how heavy they pick/string gauge, playing volumes,
war toys, etc...
Back in the spring, Mr. May emailed me several times for answers to many
very basic guitar amp related questions, it was obvious from the questions
that his knowledge of the subject was very limited. Mr. May is not the
first to come in with guns a blazin' apparently trying desperately to gain
instant credibility. Unfortunately, it only comes across as mildly amusing
entertainment.
Tim
A great amp can make a lousy guitar sound great.
A lousy amp will make a great guitar sound lousy.
Gary Carangelo
Thanks Teleologist.
I couldn't have said it better. Unlike Skippy, I don't overanalyze every
little smidgen of data to prove that I'm worthy of a brain.
GC
Quadreverb
>
>Well, then Andy... we have a hand from the audience with more dis-
>information.
>You might take a moment to re-read the earlier posts and LV's responce. I
>also followed up with an oportunity for others to comment. LV's reply is
>not clear although I gave him leave to repost his final version of how
and
>where the screen current goes. I don't see anything good you have to
>offer except some bad language which makes you look real bad.
Please explain the disinformation.
>I haven't seen to many guitar amps with High Voltage above 1KV. My fluke
>meter easily goes up to 1kv. Any tech should trust his skill and test
>equipment or he/she should be inside an amp in the first place.
Oh, 500 volts isn't high enough for you? I don't think you've ever been
inside an amp, there skippy. Getting shocked happens sometimes, and I'll
go for the cathode resistor every time if it's there. Sometimes leads
slip, too. That's precisely the reason that I put the cathode resistoron
my project amp in there in the first place, so the chances of getting
shocked or slipping a lead won't be as large.
>Well, well Mr LV lapdog. The above mistake pretty much sums it up for
>your technical knowledge. Go back and read the reply from LV as he did
get
>this one right. I also gave him credit for doing so...
So I read the freakin manual wrong about the specs on the diode. Big
freakin deal.
>Folks, my intent is not to pick on LV or Andy, only to make you aware
that
>Lord, god and guru types should never be taken as fact. Please refer to
>the earlier posts, make your own mind up. It's much easier to get in line
>that stand out.
Who's standing in line? I agree with what LV says. Besides, he's a fellow
squid. We Navy brethren stick together.
To all who are reading this, I hope it's entertaining. This guy want's to
be as funny as LV, but it's not working out. The rest of us have to make
up for it.
Andy
Lord Valve
In <33E980...@thistime.thanks> Skip <nos...@thistime.thanks> wrote
it all down in a tear-stained letter, to wit:
>
(much snippage)
>> >First Off:
>> >In your (Robert Hull's) previous post which adds a parallel
resistor/diode combination
>> in
>> >the cathode lead to measure current by the voltage drop across the
>> >resistor: What exactly does the diode do in circuit?
>> LV: Nothing.
>>
>LV is right, it does waste about 19 cents for a good diode.
>
>> >Would the diode ever forward bias?
>> LV: Nope.
>
>Pretty much, diodes are sometimes used to prevent certain component
>damage when big meltdowns occur.
actually. Of course, the tube would have smoked long before this, so
my answer is substantially correct.)
>>
>> >What would this mod do to the stabilty and or tone of the amp?
>> LV: Nothing. And I wouldn't call putting a 1-ohm resistor in
series
>> with the cathode a 'mod'; it's just a measurement convenience.
>>
>Wrong LV, when Leo Fender sold Fender to CBS, the engineers were
allowed
>to place these type of mods in the amps to "tame them down", or make
>them more reliable. This is usually refered to as the black face to
>silver/white face era. Ask any vintage dealer which amp is worth more.
>Also tell us how the bias was set at the factory...? Although this mod
>is a simple one, I wouldn't want it in my amplifier. Carbon resistors
>change value with age, metal film resistors have reactance even at low
>values. Be your own judge folks...
if you've ever even SEEN a guitar amp!! ROFL!! PLEASE...tell us how a
ONE OHM resistor in series with the cathode of a guitar-amplifier power
tube will be seen as anything other than a straight wire by the tube.
Huh? Pretty please? Fender cathode bias resistors were 150 ohm,
7-watt jobbies...and those amps were a combination of fixed and cathode
bias, to boot. (See the Dual Showman Reverb AB568 schematic for a
typical setup. You..uh...you DO know how to read a schematic, right?
And you have a few? I mean...for GUITAR amps, yes? Just checkin'...)
Now, for a fixed-bias design, we're looking at a potential difference
between the cathode and the grid of -52 volts (or thereabouts) at
idle...I realize that you know so VERY much more than all the rest of
us on this NG, but...Skippy, ol' pal...are you gonna hip us as to how
in the hell the 30-40 MILLIVOLTS that the 1-ohm resistor will subtract
from the cathode-grid difference voltage is gonna do anything audible,
or in any way at all affect the performance of the amplifier? (I
promise not to hold my breath, son...)
>
>> >Most of all, what's wrong with this method of measuring bias?
>> LV: I know what you'd like me to say...that it doesn't take screen
>> current into account. OK, it doesn't. So what? A couple of
milliamps
>> is negligible...we're not looking for laboratory accuracy or trying
to
>> achieve some absolute value here; we're just looking for the best
tone.
>> The bias point necessary to achieve that tone may fall anywhere
within
>> (or even outside, if lower) the published (or actual) specs for the
>> tube. As long as you're not crowding the high end of the current
spec,
>> this is a non-issue. Besides, you would tend to err on the LOW side
of
>> the spec, since the screen current would be ADDED to the cathode
>> current with this method.
>>
>Here we go with foot in mouth again for LV. Explain to me LV where
the
>path for this screen current goes if not through the cathode?
would it come from! Skippy, do you need glasses? Or is this a reading
comprehension thing...hmmm...
You way off base here.
LV: I is? (Your grammar, but, hell...I'm flexible...)
The cathode contains the sum of the grids and the anode.
LV: Duh. Thanks, prof.
>Only in higher power radio transmitting tubes are you likely to see
any
>reverse screen current which doesn't apply here at all.
LV: Why mention it, then?
>Your last line about "added to the cathode current" may be your only
>way to explain your way out of this one... please do so.
LV: What's to explain? From what I've read elsewhere on this thread,
EVERYONE ELSE knew exactly what I was talking about. What I said was
that the screen current would induce a small error into the quiescent
current measurement. Is this a mystery to you for some reason? If we
measure 35 ma (35 mv) across the 1-ohm cathode resistor, and 2 ma of
that is screen current, then it stands to reason that the remaining 33
ma is plate current, yes? C'mon, Skippy...you're gonna hafta do a lot
better than this...
(more snippage)
>> LV: Personally, I like 'em on the hot side. Power tubes are (or
>> should be) designed to run at the proper temperature WITHOUT
additional
>> cooling, as long as specs are not exceeded. Tubes designed to burn
>> base-down which are being operated base-up could possibly derive
some
>> slight additional longevity from fan-cooling, but this would be more
>> beneficial to the plastic base than to the metal parts inside the
tube.
>
>There are other factors which come into play here LV. All tubes derive
>benefits by cooling of the base and external anode metal pins.
LV: So? Nearly impossible with 'small' tubes like guitar-amp power
tubes. Non-issue.
Air
>movement around the glass is fine, but no where near as effective as
air
>flowing around the metal pins. This would be a great place to
establish
>this fact. Have a look at large tube applications.
LV: Why? There is very little extra real-estate in a guitar amp,
which must be small enough and light enough for a musician (you
remember those dudes, right, Skippy? They're the folks who actually
USE this gear...) to move it from gig to gig. Please tell us how you
are going to install some cumbersome pin-cooling system in a Deluxe.
We're not talking 50KW radio-station finals here, dude...try to stay on
topic. "GUITAR" amplifiers, ok?
(snip)
>
>> As far as the glass goes...if it were pure, it probably wouldn't
heat
>> up much at all. Most of the heat which leaves a tube does so as
>> infra-red radiation, and it goes through the glass like it wasn't
even
>> there. Only impurities in the glass (and dirt on the surface, which
is
>> why I always hit the tubes with some Windex when I'm doing
maintenance)
>> can absorb this radiation, thus gradually raising the temperature of
>> the bulb. (Some heat is added by direct conduction where the wires
>> exit the bulb, too.) Heat from the bulb is re-radiated (at a much
>> slower rate) at a different frequency of IR. (Lower, I think...)
>
>Well, you got your foot in your mouth again over the above, but the
>addtional posts set your straight. All you others should go back to
the
>original thread to read the information others followed up with. It's
>on the money...
LV: Yes, it is...however, in order to be EXACTLY sure I'm "wrong",
you'll have to tell us in which part of the IR spectrum the bulk of the
heat radiated by the plates lies...because if it's in a portion of the
spectrum to which glass is relatively transparent, then I'm more
"right" than you are. Mexican standoff, si?
(snip)
>> >should have your bias checked? What would this change be?
>
>> LV: I reckon that as the cathode degrades over time, we'd want to
>> lower the bias voltage slightly to suck them trons a leetle bit
harder.
>> This would increase the current back up to the optimal point.
>> Remember, though...we're lookin' for TONE here, so I'd only adjust
the
>> bias if the musician complains about the way the amp sounds.
>> >
>
>You might do this LV, I wouldn't. Have you ever measured the
distortion
>that occurs when you move the bias to a non linear portion of the
>operating curve?
LV: Have you ever asked the guy who owns the amp if he LIKES it that
way? As long as the tube is not being damaged...who will give
000000091 of a rodent's posterior about 'non-linear' operation? Only
you, Skippy, and that pack of anal wankeroid magic-wires enthusiasts
over on RAT. I suspect.
The only real fix is to replace an old tube or increase
>the heater voltage (with the coresponding decrease in lifespan), not
>practical in most amplifiers but often done in higher power tube
>equipment. Leave the bias set in the linear operating area where it
>belongs.
LV: (See above.)
>
>> >An amplifier with the bias set wrong could have higher
idle/operating
>> >current and run hoter within it's ratings , but the amount of power
>> the
>> >tube can handle, remains the same. If the tubes are biased wrong
but
>> still
>> >within their ratings, how will tube life be greatly reduced,
Robert?
>> >Anyone? Details please?
>
>> LV: It wouldn't.
>>
>Well, he got this one right...
LV: Jeez...Skippy's getting better at reading comprehension...
>
>> LV: The 'best' way to bias an amp is the one that makes it sound
the
>> way the musician likes it to sound. There are several different
>
>Even if it's not right, keeps the customer comming back. Right or
wrong
>that seems to be the way of life...
LV: Skippy...the customer keeps coming back (and has done so for
nearly 30 years now) because...I realize this may be a difficult
concept for ya, son, but bear with me a minute, here...HIS SHIT KICKS
ASS when I'm through working on it. (Imagine that...satisfied
customers! See? I TOLD ya this would be difficult for
ya...capitalism, no? More on THAT subject later...)
>
>> ways...cathode resistor, plate resistor (for you accuracy freaks),
>> output transformer primary shunt method (scary, and not all meters
can
>> do it), the crossover notch method, the 'by ear' method (which
usually
>> starts out with one of the other methods to get into the ballpark,
and
>> finishes up with some listening/diddling/listening/diddling action),
>> and the harmonic distortion meter method. I've used 'em ALL at one
>> time or another. I routinely use the crossover notch method on
older
>> Marshalls; I seem to be able to achieve what my customers want on
those
>> amps with a scope and my eyeballs.
>
>Not much information here, just bragging.
LV: I'm reminded of a quote attributed to Babe Ruth: "It ain't
braggin', if ya can DO it." ('Nuff said.)
But setting an amp is a
>compromise. I always use a scope and a meter. I've never seen a
perfect
>amp but the scope will help me get it to the best place it's gonna be.
LV: WOW! This deserves an entire additional post! Check for
"SKIPPY'S FULLA CRAP, Part Two..."
>
> For Fenders, I like the cathode
>> resistor method; many times, I'll finish up by ear, if the customer
is
>> in the shop at the time. (Sometimes, I gotta do my own pickin' and,
>> well...I, er...play the guitar like you'd imagine an organist would.
>> Badly!!) Most Ampegs aren't adjustable, so I usually do a
transformer
>> shunt check to make sure things are in the ballpark. A peek at the
>> quiescent current draw for the entire amp is in order here, also. I
>Buzz words,
LV: Hmmm...exactly which words started you buzzing? Are you sure
you're not suffering from some sort of electroencephalitic oscillation,
Skippy?
>
> I don't like transformer shunt checks.
They tend to place a
>strain on older transformers. I've seen two go away in a guys shop
>during a shunt test.
LV: Lord Valve will watch with great interest while Skippy explains to
the entire Usenet how REMOVING the current from one leg of the output
tranny's primary will "strain" it. The Lord will also await posts from
the other techs (sorry, Skipper...you don't qualify for this one) on
this NG as to exactly how many trannies have croaked from this
practice.
(major snip)
I don't use a spell check program.
LV: No kiddin'. Neither do I, Skipper...see the Babe Ruth quote
again, if you require enlightenment on this.
(snip)
>I have nothing to hide or sell on the newsgroup.
>You may have nothing to hide, but your always trying to sell us
>something.
LV: EGAD!!! Skippy's bummin' out over Capitalism. I TOL' y'all he
was one o' them Ivory Tower Lefties, didn't I? I got it, now...he's a
Clintonista...you know...those .edu-cats who carry around a copy of the
Little Red Book in their hip pockets, in lieu of a wallet? You are
ABSOTIVELY, POSOFUGGINLUTELY RIGHT, Skippy. I own a music store. I
sell stuff ALL DAY LONG, and if I can figure out a way to do it all
NIGHT long too, I'm gonna do it. Occasionally, I post a "LORD VALVE'S
SPAM LIST" article, where I invite people to REQUEST advertisements via
e-mail from me. To date, (8/8/97) 663 people have requested this.
Many of these people have bought tubes, speakers, repair parts, etc.
from me. I invite any one of them who has been in ANY way dissatisfied
with anything they ever bought from me to snip this portion of the
thread, re-name it "LORD VALVE RIPPED ME OFF", and post the details.
Capitalism is a two-way street, Skippy...BOTH parties must be satisfied
with the transaction for it to survive. (I realize that this is a
startling concept, and not seen all that often on America's campuses.
Go figure.)
Lord Valve
spa...@njammin.com
SPAMpre...@hotmail.com
Man... what's going on with Skip!
While I'm personally not interested in bogus information in this
newsgroup, I'm not that disturbed by the "gross errors" that Skip's
felt he's needed to point out regarding Robert's & LV's posts.
I haven't felt that either of these guys have mislead anyone in this
newsgroup. Their input has been very practical and "real world", even
if it hasn't been MIL-SPEC (kinda like setting the torque spec. on an
oil filter!!!). Fact is, I've benefitted from their input - their $.02
is worth at least double that in my book! ;-)
Bottom line, if provocation is what Skip (or anyone else) is after,
then I believe this is really the wrong forum.
<= $.02 worth,
Predacaster
P.S. Regarding the "religion" remark, it's not that people have been
well-intentioned but ignorantly incorrect for 30 and/or more years.
Rather, they've seen what IS right, and gravitate toward the wrong
instead.
To e-mail, remove SPAM from address.
Dave Harris
>
> A trick for large amplifier and power supply meter protection is to place
> two "back to back" diodes on the meter terminals. The diodes will shunt
> the excessive current hopefully saving expensive meter movements. Pick
> up a copy of the ARRL Handbook where this "trick" is often described.
> skip
A meter is worth something and therefore worth protecting. A resistor is
worth nothing. Fitting a diode to protect it is bad news. The early death
of the resistor could protect your transformers. Now they are worth
something !
Dave
Mark L.
Skippy!
You've made the wagons form a circle!....
Where's that "Wagons HOOOOoooooow" fella??
Pete Kerez
In article <19970808013...@ladder02.news.aol.com>,
tomh...@aol.com (Tom HIWATT) writes:
>I leave for a while and look what happens.
>
I haven't been here at a.g.a very long, don't know much electronics, but
evertime i read one of those Skip May posts my IBD (Infallible Bullshit
Detector) starts beeping LOUD, which just doesn't happen when i read posts
from The Valvester.
Texas Pete
Pete Kerezman (pete...@aol.com)
Alex Tobias
cpec...@aol.com (CPecoraro) wrote:
>>mature than that & it does absolutely nothing for your credibility.
> The man knows his shit about amps....
>Amps are not just circut boards that you can bench test, pull
>a resistor, solder that ect.. They are more like people,...
>every one is different, every guitar player is looking for "the tone" So
>standard therory does not always hold water. It is better
>you have booked based knowledge, seasoned with street smarts
>that can only come with in the field front line warfare.
> So get off LV, he has the years of field experience,
>and "hands on " knowledge that can't be replaced by any books.
> That gives him the right to be opinionated.
> I opologize for my terrible spelling, and
>piss poor
>syntax, grammar and shit.
> Chuck
That's some pretty stupid commentary...I think the original poster's
point was that no one has all the answers and that people should never
take for gospel what they read on usenet...
IMO that's some pretty sane advice....
Not to mention LV has done some slamming himself on here and he is a
big boy and can take some back without shedding too many tears...
Jeremy Epstein
In article <5segig$2...@dfw-ixnews12.ix.netcom.com>,
detr...@ix.netcom.com(Lord Valve) wrote:
<snip>
> Occasionally, I post a "LORD VALVE'S
> SPAM LIST" article, where I invite people to REQUEST advertisements via
> e-mail from me. To date, (8/8/97) 663 people have requested this.
> Many of these people have bought tubes, speakers, repair parts, etc.
> from me. I invite any one of them who has been in ANY way dissatisfied
> with anything they ever bought from me to snip this portion of the
> thread, re-name it "LORD VALVE RIPPED ME OFF", and post the details.
I thought the free pen you threw in with my STR7025's was sorta
cheap-lookin' and I wanted a free Space Pen so I could write upside-down.
Since you asked.
-j
-------------------==== Posted via Deja News ====-----------------------
http://www.dejanews.com/ Search, Read, Post to Usenet
Tremolux
Hey Skippy, LV is right. I always use the transformer shunt method for
checking bias, and I've NEVER seen a tranny croak. How could it unless
you fuck up and short something to ground?
Skippo, my man, you're fighting a losing battle here. Best to cut your
losses and retreat.
Jeff Vineburg
>What is this, the Spanish Inquisition???
No one expected it...
My $.03:
One of the things I am learning is that what you DON'T play is just as
important as what you DO play. It's the space between the notes.
Applying this to usenet, what you DON'T post is ever more important
than what you DO post.
Although I am guilty of this too, we seem to get too caught up in
personal attacks, or seeing things as personal, so we step up to the
keyboard and FIRE BACK.
If Skippy or LV chose to post an opinion that stated that right-handed
folks play better than left-handed folks, I'd be tempted to flame them
into eternity. Everyone knows it's simply not true. In fact, the
opposite is correct.
But I'd try to get hold of my temper and explain to them (S-L-O-W-L-Y,
if necessary) why they're totally mistaken. If they persisted in this
extreme form of ignorance, I'd have to let my playing speak for me.
There's a point in there somewhere.
--------------------------------------------------------------
Jeff Vineburg !je...@op.net! Nuclear Fish !je...@nuclearfish.com!
http://www.op.net/~jeffv http://www.nuclearfish.com
lefty guitar info, musical humor song parodies, as heard on Stern show
Joe Cocker Spaniel's page
Gary Carangelo
Hey Guys,
Maybe Skippy could try his hand at selling used cars.
Where's P.T.Barnum when you need 'em?!.
GC
Thomas C. Clancy
In article <5sd487$9...@ds2.acs.ucalgary.ca>,
Scott Hinman <ashinman@chem.?ucalgary?.ca> wrote:
>Skip wrote:
>expected him to be aware of the distinction. (You're not an infrared
>spectroscopist, are you LV?). Your reply to LV makes me wonder if you
maybe a microwave (oven) spectroscopist.
TimTube
In article <5segig$2...@dfw-ixnews12.ix.netcom.com>,
detr...@ix.netcom.com(Lord Valve) writes:
>>strain on older transformers. I've seen two go away in a guys shop
>>during a shunt test.
>LV: Lord Valve will watch with great interest while Skippy explains to
>the entire Usenet how REMOVING the current from one leg of the output
>tranny's primary will "strain" it. The Lord will also await posts from
>the other techs (sorry, Skipper...you don't qualify for this one) on
>this NG as to exactly how many trannies have croaked from this
>practice.
This practice would if anything provide some relief to a transformer how
can the transformer be over-taxed by shunting current from it???.
Sounds like Skippy's method must be one lead to the plate and the other to
ground, with a 20amp HT fuse. This method would indeed yield the results
described by ampmaster Skippy.
Skip May
TimTube (tim...@aol.com) wrote:
: In article <33E980...@thistime.thanks>, Skip <nos...@thistime.thanks>
: writes:
: >
: >> LV: The 'best' way to bias an amp is the one that makes it sound the
: >> way the musician likes it to sound. There are several different
: >
: >Even if it's not right, keeps the customer comming back. Right or wrong
: >that seems to be the way of life...
Of course both the above are snipped out of context, but no big deal. In
my other responce to Joe, please refer to the example where your amp comes
back from repair which includes diodes and resistors that you don't need
for a $75 price tag... make up your own mind.
:
: Out of all of the spewing BS in this post, I found the above snippet to be
: the most annoying.
:
: It is only "right" when the musician/customer likes it. Some like 'em
: hotter than others.
I agree, wouldn't a properly biased amplifier sound good? Wouldn't you be
able to "heat up" an amplifier's sound with various choices in tube gain?
I think grove tube makes a business doing such a service...
Maybe we need better labels for distortion vs hotter/gain?
: The ideal way for me is much like LV's, dial it in to
: a known good value, play it, or better yet, let the owner play it at
: playing condition volumes readjust, up or down to find the "sweet" spot.
I don't have any problem with this. I also don't need to add diodes and
resistors to do it.
: Then remeasure to make sure they are not running too hot. If they are
: running a little high, say 40-45 for a 450V Fender 6L6 amp, dim the lights
: and make sure the plates aren't red, then let the owner decide if the
Red plates are not a good thing, even being close is not a good thing f¿r
long periods..
: wants to sacrifice tone for tube life. I've set amps for owners this way
: with settings from 20 to 45 ma. There are many factors to consider, the
: output of the guitar, how heavy they pick/string gauge, playing volumes,
: war toys, etc...
:
You are very right about all the above, except you leave out excessive
heater voltage, a major killer... Matter of fact, I don't see any one who
has mentioned it before, even Joe with his extensive transmitter
experience. One of the firs things done to a tube transmitter is to set
the heater voltage.
This next part is really off base... here we go
: Back in the spring, Mr. May emailed me several times for answers to many
: very basic guitar amp related questions, it was obvious from the questions
: that his knowledge of the subject was very limited. Mr. May is not the
: first to come in with guns a blazin' apparently trying desperately to gain
: instant credibility. Unfortunately, it only comes across as mildly amusing
: entertainment.
:
Yep, he's right. I emailed him to ask the difference in configurations of
Marshall by model numbers. Before I purchased The History of Marshall, I
wanted the model numbers and configurations of the 2205 and the 2204
preamps. Now I have the book (which I highly recomend), I've been able to
locate various Marshall circuit diagrams to obtain what I need.
Get the book, worth every penny at $32 US, but you better ask LV or Tim
first.
Here again folks we see miss-information to move off topic. Feel free
only the topics, add information, hints or add your own two cents. I
would prefer to keep the language civil though. If you see the Titanic
leaving the dock, ask why the boats full of resistors and diodes before
you board.
: Tim
: A great amp can make a lousy guitar sound great.
: A lousy amp will make a great guitar sound lousy.
:
Thanks Tim and everyone... I've got the wagons in a circle now...
Skip May
Mark L. (mj...@mail.idt.net) wrote:
: Skippy!
:
: You've made the wagons form a circle!....
:
: Where's that "Wagons HOOOOoooooow" fella??
Thanks Mark... which side of the circle are you on...?
The bullets might be heading your direction, get down... better yet stand
behind someone...
cheers
Skip
nosp...@juno.com
Ned Carlson
Lee MacMillan <"lee$macmillan"@worldnet.att.net> wrote:
>> The billboard says "There's More Than Corn in Indiana!"
>> Yup, POPcorn, too, and lots of it.
>Orville Redenbacker was Indiana's gift to popcorn.
Yeah, I forgot about Orville, we was from Valpo,
wasn't he?
>
>> I gotta give dem Hoosiers credit, they made Duesies there,
>> and if that wasn't the World's Greatest Car, you kin
>> chomp my popcorn...
>Yep, those Studebakers were really duesies!
I've a few Studies, I liked that flathead 6 '50 Land Cruiser
a lot. Ever change a Hill Holder?
Ned Carlson, Triode Electronics, Chicago, IL http://www.triodeel.com
Open 12:30-8 PM CT, 12:30-5 PM CT Sat Closed Wed
ph:773-871-7459 fax 773-871-7938 "where da tubes are"
Email catalogs: email our CataBot: cat...@triodeel.com
Ned Carlson
Jeremy Epstein <7066...@compuserve.com> wrote:
>I will leave the relative rankings of these four New Haven pizzerias as
>an exercise for the reader - there is a lot to be said for each of them.
>As an aside, Tony & Lucille's, also in the same area, makes a mean
>calzone.
Sounds like a good recommendation to me!
>I've heard that you Chicagoans try to pass off some sort of deep-dish
>thing that looks like a fritata gone bad as pizza, but I'll withhold
>comment on that stuff for now.
Really, that stuff was invented by a Texan....!
There's plenty of other kinds of pizza here, note I've
developed quite a taste for Thai & Mexican, and all that
cheese kinda plugs me up, so I've gotten a little rusty on the
pizza tasting.
OK, I shoulda shut up.
I can't say I like pizza better than enchiladas anyway, just in case
my wife learns how to use Deja News...
>By the way, a place near my house in Carroll Gardens, Brooklyn, has t
>right idea - an awesome thin-crust, fresh-sauce, coal-oven pie, preceded
>by a free appetizer : a full head of roasted garlic for the table. Next
>time you're in the NY area, please look me up and we'll go!
Sounds good to me...might be a while 'til I get there..thanks!
TimTube
In article <5sg5cr$phs$2...@mark.ucdavis.edu>, sk...@dilbert.ucdavis.edu
(Skip May) writes:
>
>: wants to sacrifice tone for tube life. I've set amps for owners this
way
>: with settings from 20 to 45 ma. There are many factors to consider, the
>: output of the guitar, how heavy they pick/string gauge, playing
volumes,
>: war toys, etc...
>:
>You are very right about all the above, except you leave out excessive
>heater voltage, a major killer... Matter of fact, I don't see any one
who
>has mentioned it before, even Joe with his extensive transmitter
>experience. One of the firs things done to a tube transmitter is to set
>the heater voltage.
"Heater Voltage, a Major killer"??? Let me guess, the title of ampmaster
Skippy's disertation? What a crock 'o crapola. This guy is either a brute
for punishment, or just starved for attention. He can sure conjour up some
BS.
Ampmaster Wannabe Skippy, how many guitar amps have you seen that have
been killed by exessive heater voltage...err lets simplify it, how many
guitar amps have you seen???
Pat Lyman
Skip May wrote:
> I agree, wouldn't a properly biased amplifier sound good? Wouldn't you
> be
> able to "heat up" an amplifier's sound with various choices in tube
> gain?
> I think grove tube makes a business doing such a service...
>
> Maybe we need better labels for distortion vs hotter/gain?
>
If you mean by "properly biased", an amp is set purely by
instrumentation, then it probably won't sound good to most guitarists
whom I've shared the stage with on paying gigs.
If your definition of "properly biased" is tuning that particular
parameter to the musician's taste, regardless of consequences to tube
life, then you're getting close.
I've never had a problem acknowledging that "sounding good" is more
desirable than "lasting longer." I'm a bass player and I change $20
sets of bass strings every 3 or 4 gigs BECAUSE I LIKE THE SOUND of fresh
strings, and, being a paid musician more than defrays the cost. I've
heard amps that were biased "by the book" and amps that were tweaked to
sound hot. Any guitarist that I know prefers the latter and hang the
cost. The difference is quite apparent to other musicians in the
band. A guitar amp is not a simply a device to turn little signals
into big ones. From the preamp to the speakers, it is very much a
continuation of the tone production and manipulation process.
My Alembic preamp is one of the most non-linear devices there is to be
had (and Alembic will happily confirm this), and it sounds great. It
also sports a tube I've bought from L.V., which made it audibly better
to not only myself, but the guitarist whom I work with most often. I'll
bet he made a profit from the sale, and I'm glad he did. Tomorrow I'm
going to make a nice profit making a Novell network perform. Tomorrow
night I'm going to make less of a profit (but have more fun) playing
blues in a bar. I love and support free market capitalism!
Aspen's rating system just does not have enough variation (or
credibility, to many) to provide the ad hoc changes in sound this thread
appears to be pursuing. If you read the ads carefully, the ratings are
there to provide consistency (not choice) in sound for the road musician
who has tube failure while out there and needs a quick replacement.
My bachelor's in electronics led me down a path to computers, then to
data analysis. Hence, I leave the tube info acquisition and dispensation
to those whose advice is consonant with my own empirical observations.
Music supported me through my senior year, and 20 years later, I still
enjoy 1 to 3 paying gigs a weekend. It keeps me feeling human. When it
comes to amps, or actually almost anything in life, I'll listen to the
person whose done it for a living for a couple of decades over the
recent college grad. Most successful (in life) college grads I know do
the same thing. They (we) also recognize that a degree, or book
knowledge in general, is but one tool to be utilized in pursuit of
whatever floats one's boat. Real life experience is where it's at.
I mention this because it is a fact apparently ignored by one of the
sides in this thread.
Andrew McWhirter
I don't usually join in on these flame wars, but I can't hold my tongue
this time.
I apologise in advance if anyone feels that my editting of the post here
distorts the facts in any way... I tried not to.
Skip, you might mean well, and your warnings about being cautious of
what some posters say is not *bad* advice (hell, I mean it's
Usenet....no one really expects the 'whole truth and nothing but the
truth'). But your attack on his Thermionic Radiance, Lord Valve, is out
of line. I think your problem is that you only look in here
periodically - your post I believe->
> >I drop by the news group here to see what's cooking about twice a
> > week.
>> LV: Since he's posting from an .edu domain, chances are rather
>> good that he's one o' those cats who are long on book-learnin'
>> and short on stage time...
> First off, when you see or hear someone attack something that has
> nothing to do with the topic, this is usually a diversion ploy. Lord
> Valve, my domain has nothing to do with my education, job, experience
> level or the facts at hand.
See how LV said 'chances are rather good'...? Correct him if you like.
Tell us what your background is....why should we listen to you? If you
read this newsgroup regularly you would know Willie's background is no
secret, and is not to be scoffed at as far as I'm concerned. Consider
this an invitation to give yourself some credibility.
> > LV: Nothing. And I wouldn't call putting a 1-ohm resistor in series
> > with the cathode a 'mod'; it's just a measurement convenience.
> >
> Wrong LV, when Leo Fender sold Fender to CBS, the engineers were allowed
> to place these type of mods in the amps to "tame them down", or make
> them more reliable. This is usually refered to as the black face to
> silver/white face era. Ask any vintage dealer which amp is worth more.
> Also tell us how the bias was set at the factory...? Although this mod
> is a simple one, I wouldn't want it in my amplifier. Carbon resistors
> change value with age, metal film resistors have reactance even at low
> values. Be your own judge folks...
Ok, I'll have to assume you've done this to hundreds of amps and you can
hear the difference. What a pile of crap.... Tell us about the
inductance of a 1-Ohm resistor, Skip.... There was a thread here a
while back on inductance in resistors (or it may have been on
rec.audio.tubes) If the only thing CBS had done to Fenders' amp line
after '65 was to add a 1-Ohm cathode resistor, no-one would give a shit
(well, maybe some collectors, but not players) about BF vs SF. I was
under the impression that there is no difference between some SF/BF
models *at all*, and that some others the changes are relatively minor
(but, granted, some others were completely stuffed around with). None
of which is directly reflected in their value to vintage dealers. And
before you flame away at me, let me just say that I am no amp expert.
> > >Most of all, what's wrong with this method of measuring bias?
> > LV: I know what you'd like me to say...that it doesn't take screen
> > current into account. OK, it doesn't. So what? A couple of milliamps
> > is negligible...we're not looking for laboratory accuracy or trying to
> > achieve some absolute value here; we're just looking for the best tone.
> > The bias point necessary to achieve that tone may fall anywhere within
> > (or even outside, if lower) the published (or actual) specs for the
> > tube. As long as you're not crowding the high end of the current spec,
> > this is a non-issue. Besides, you would tend to err on the LOW side of
> > the spec, since the screen current would be ADDED to the cathode
> > current with this method.
> >
> Here we go with foot in mouth again for LV. Explain to me LV where the
> path for this screen current goes if not through the cathode? You way
> off base here. The cathode contains the sum of the grids and the anode.
> Only in higher power radio transmitting tubes are you likely to see any
> reverse screen current which doesn't apply here at all.
> Your last line about "added to the cathode current" may be your only way
> to explain your way out of this one... please do so.
C'mon, admit it....you got no idea at all what's being discussed here,
have you? Again, this has been discussed in this NG to death. There
was a very informative post a couple of months back where someone
(sorry, I can't remember who did the work!) had gone to the trouble of
measuring the error in biassing using the cathode resistor method.
Another one for you to look up.
> > >>fans, that is probably the best way to keep everything cooler. Find
> > >>some way to direct a fan on to the tubes.
> > >
> > >Wrong! Where's does this fact come from Robert? Isn't glass an
> > insulator?
> > >
> > >BETTER THAN 50% OF THE TUBE AMP GURU'S HAVE THIS WRONG! Maybe after
> > Robert
> > >has a chance to comment (along with others), I'll provide the facts.
> > LV: Jeez, dude...don't do us any favors...
> There are other factors which come into play here LV. All tubes derive
> benefits by cooling of the base and external anode metal pins.
We're still waiting for the lowdown on this one.... Seems to me that
any ventilation (assisted by a fan? Yeah, why not?) is better than
letting the amp cook in it's own juice. Maybe won't do all that much
good, but can it hurt? I read another opinion here that fans might
assist in keeping other components (resistors and capacitors) cool, and
thereby extend their life. Again, maybe that's hearsay, but can it
hurt?
Now, from you we get:
> I didn't see you offer any hints here LV, care to comment before my
> followup post about this area...?
(personally, I'm on tenterhooks....)
but immediately following, and copied in your own post we see:
> > LV: Personally, I like 'em on the hot side. Power tubes are (or
> > should be) designed to run at the proper temperature WITHOUT additional
> > cooling, as long as specs are not exceeded. Tubes designed to burn
> > base-down which are being operated base-up could possibly derive some
> > slight additional longevity from fan-cooling, but this would be more
> > beneficial to the plastic base than to the metal parts inside the tube.
Perhaps you can tell us why you didn't see LV offering hints? Sure
looks like he did, to me....
> > As far as the glass goes...if it were pure, it probably wouldn't heat
> > up much at all.
<snip>
> Well, you got your foot in your mouth again over the above, but the
> addtional posts set your straight. All you others should go back to the
> original thread to read the information others followed up with. It's on
> the money...
Which he graciously accepted. You'll do the same, I'm sure....
> > LV: I reckon that as the cathode degrades over time, we'd want to
> > lower the bias voltage slightly to suck them trons a leetle bit harder.
> > This would increase the current back up to the optimal point.
> > Remember, though...we're lookin' for TONE here, so I'd only adjust the
> > bias if the musician complains about the way the amp sounds.
> > >
>
> You might do this LV, I wouldn't. Have you ever measured the distortion
> that occurs when you move the bias to a non linear portion of the
> operating curve?
And distortion is a bad thing in guitar amps, right? Oh, that would be
why so many people buy stomp boxes to add distortion or overdrive
pre-amps and stuff like that. This is a joke, right?
> The only real fix is to replace an old tube or increase
> the heater voltage (with the coresponding decrease in lifespan), not
> practical in most amplifiers but often done in higher power tube
> equipment. Leave the bias set in the linear operating area where it
> belongs.
Who said anything about moving into (seriously) non-linear regions,
anyway? You seem to be under the impression that there is one quiescent
operating point only? News to me.... And if you bias to this magical
linear operating region, they'll never distort no matter how hard you
push them?
> > Let's filter the technoblather out
> > >What's the best way to bias an amp Robert? Anyone?
>
> > LV: The 'best' way to bias an amp is the one that makes it sound the
> > way the musician likes it to sound. There are several different
>
> Even if it's not right, keeps the customer comming back. Right or wrong
> that seems to be the way of life...
You *seem* to be saying that techs will happily set up an amp so it'll
blow up sooner and they'll come back for more bench time. Yep, that's
right, all amp-techs are a bunch of crooks, getting rich along the way.
> > ways...cathode resistor, plate resistor (for you accuracy freaks),
> > output transformer primary shunt method (scary, and not all meters can
> > do it), the crossover notch method, the 'by ear' method (which usually
> > starts out with one of the other methods to get into the ballpark, and
> > finishes up with some listening/diddling/listening/diddling action),
> > and the harmonic distortion meter method. I've used 'em ALL at one
> > time or another. I routinely use the crossover notch method on older
> > Marshalls; I seem to be able to achieve what my customers want on those
> > amps with a scope and my eyeballs.
>
> Not much information here, just bragging.
Read the group more often, Skip. LV has detailed the methods more times
than you can imagine. Got a specific 'how to set the bias on my ABC123
amp' question? Ask away!
>LV: > For Fenders, I like the cathode
> > resistor method; many times, I'll finish up by ear, if the customer is
> > in the shop at the time. (Sometimes, I gotta do my own pickin' and,
> > well...I, er...play the guitar like you'd imagine an organist would.
> > Badly!!) Most Ampegs aren't adjustable, so I usually do a transformer
> > shunt check to make sure things are in the ballpark. A peek at the
> > quiescent current draw for the entire amp is in order here, also. I
>
> Buzz words,
What are the buzz words?
> I don't like transformer shunt checks.
Neither do lots of other folks...but never heard this reason before:
> They tend to place a strain on older transformers.
> I've seen two go away in a guys shop during a shunt test.
Ok Skip, enlighten us.....how can shorting out the HT side with a meter
blow up (make them 'go away' - what does that mean, BTW?) an O/T?
> > have a snazzy HP harmonic distortion meter, too, but I usually only use
> > it on high powered SS PA amplifiers...gee-tah pickahs invariably like
> > more harmonic distortion than the lowest that can be achieved, for some
> > reason.
>
> It's that what overdriving tube amps are about?
If you wrote a complete sentence, I might have some idea of what you
were trying to say here. FWIW, I think that LV was talking
tongue-in-cheek. Maybe I'm the only one who read it that way.
> > Lord Valve Speaketh:
> > Well, Skippy...I've addressed a few of the questions you've raised,
> > acuurately, I think...
>
> Not really, please try again... your attack on my domain makes no sense
> also.
It makes sense to me. You write like you are still in school.
> >but from where I sit, it looks like you're gonna
> > lay the Big Hotshit Engineer routine on us, so let me just say this in
> > advance:
>
> Is the word used anywhere with my name LV?
>
> > Everything I've written above is knowledge I've gained from
> > 30 years of field experience.
>
> I've known people who have been wrong about various things for many more
> than 30 years. Look at a lot of organized religons, a thick slice of
> bologna for many.
What has religion got to do with guitar amps?
> By the looks of your above statements, you've been
> wrong about a few things for some time.
You forgot to add 'in my opinion'.
> > Guitar amps (and my Leslies) are
> > routinely operated beyond normal parameters, and 'by-the-book'
> > procedures for testing and adjustment of these devices often does not
> > produce the results musicians desire. The 'best' methods are the ones
> > which produce the desired results; often, these methods are at odds
> > with conventional wisdom.
>
> > As an aside...I'd be remiss if I didn't
> > mention that your spelling is atrocious, your syntax is laughable, and
> > DUDE...if you're gonna diss somebody, at LEAST get his name right!
>
> I didn't notice you with a teaching degree LV? Feel free to point the
> facts out. I don't use a spell check program. I know what Roberts
> correct name is, in addition to the fact that I emailed him to look and
> comment at my posts. I have nothing to hide or sell on the newsgroup.
From where I sit, you seem to have nothing whatsoever to add to this
newsgroup. Feel free to unsubscribe whenever you like. You don't seem
to understand that what you offer us is only your opinion - nothing
more.
> You may have nothing to hide, but your always trying to sell us
> something.
That's strange... I thought that LV went to extraordinary lengths to
avoid selling in this NG. As I see it, he might mention that he can
help someone with a part or tube or whatever in repsonse to a request
for help from time to time, but never can I recall seeing a post
initiated by him saying he has something to sell us. Correct me if I'm
wrong...
Have a nice day.
Andrew
--
******** Please remove the words SPICED-HAM from my ********
******** email address to get the real address. ********
******** Sorry for the inconvenience! ********
Gary Carangelo
I think your reading into this way too much nospam.
This is probably healthy.
GC
Skip May
Tom (tma...@erols.com) wrote:
Hi Tom,
I've taken out much of the other quotes from before. I'm not sure of how
Andrews email was reposted by you, but I did sent him a nice reply.
Perhaps that will also make it on here? If not, I think I can dig up a
copy. Also a lot of this reposting is turning the comments by others into
LV's and my credit. Be sure to go back to #1 so you can read who wrote
what. As this has turned into a lapdog field day, I'll be droping the old
text as it's often duplicated. OK, time to move on...
: OK, I see no need to defend El Lardo because he jes' don' need none,
: doncha see?
I guess your refering to LV, Although I'm told he has a weight problem, I
prefer to leave it alone as it's off topic and doesn't apply here.
:I have tried the various methods of biasing, including the
: transformer shunt method (which, incidentally, I prefer), and I have
You know, there may be a little confusion here on this transformer shunt
test. After I read and reply to LV's latest diatribe, maybe we can deside
which of the two methods I know of that is being left out of the picture.
We may have two different tests going on in the topics... hey! If this is
what's going on, I may have something new to throw out... can you dig it?
: never: zapped myself, zapped any tranformer, or blown ANYthing up....I
No mistakes is a very good track record, keep it up.
: read the newsgroup, as well as any books on amps I can find, and I'm
: STILL learning after approximately 29 years of fooling with this stuff.
This is a great way of thinking! Your on the right track... but you know
that already. I'm happy to learn something new myself. I didn't know that
adding diodes and resistors to the cathode lead of and amp was a needed
improvement? I've always left amplifiers original when I could. Think of
all the $75 resistor/diode mods I've missed out on...
: I trust LV,....might differ with him sometimes, but still respect him.
I don't have a problem with LV, but I've seen his mods posted on the group
here without question. Some of which I don't agree with. These I've
brought up in my posts and replies. Then the fun started...
Remember, he responded to my post... of course I'd like to debate anything
he brings back without the personal slams or bad language. But, I haven't
seen a post from him to me yet without all the above.
I don't think much of his language or maners, but you are free to make
your own choices here. And then we have the lapdogs who bark loud at his
heels. I haven't seen or heard to many of these doggies take me to task or
debate for the facts in my posts yet. Let's hope we might..
: University-training is one thing...real-world experience is
: another...sometimes they interplay..but obviously NOT always....
: .
Again you guys bring in the University thing... Go back anywhere and see
if you can find any references from me about the University or my formal
education. As I mentioned before, this is a "poor mans diversion tatic".
Beware of diversions as "technoblather" is soon to follow.
The facts I post should stand by themselves, if not bring them to my
attention and we can talk about it in a civil maner. My hurried typing
with bad spelling is my soft spot so try to be kind there. There are a
lot of lapdogs to bark back at in the last three days...
Watch for my followup to LV's latest for my method to chassis cool an
amplifier. If you thinks it's wrong say so, to me directly and we can talk
about better methods if you have something constructive to offer.
Good luck with your transformers.
Cheers
Skip May
Robert Fries
jand...@mail2.sas.upenn.edu (James Andrews) wrote:
>Jeremy Epstein (7066...@compuserve.com) wrote:
><snip about New Haven pizzerias>
>: block but makes a worldclass pie nonetheless. And they spell it the old
>: way, "apizza," which I kinda like.
>
>Are you sure that isn't just a misspelling, like "Heresa your apizza,
>goomba?" or some other Italian stereotype?
>
I don't recall ever seeing 'apizza' in Italy - though I saw lots of pizza.
Of course, it's not as good there as in N.Y.C.
RF
>
Skip May
Gary Carangelo (GARYCA...@POSTOFFICE.WORLDNET.ATT.NET) wrote:
: Hey Guys,
:
: Maybe Skippy could try his hand at selling used cars.
:
: Where's P.T.Barnum when you need 'em?!.
:
:
: GC
:
:
Reference, Lapdog #? ... I got lost again.
Quadreverb
>As this has turned into a lapdog field day,
Skippy, you are such an ass. Are you religious? If so, does that make you
a Jesus lapdog? You are your own lapdog.
> I didn't know that
>adding diodes and resistors to the cathode lead of and amp was a needed
>improvement?
Once again, taking everything out of context and overanalyzing everything
(anal-yzing in your case). This is NOT a mod you blithering idiot! It is
merely another way to measure bias! You fool! Nobody called it a needed
improvement! Please put your head back in your ass so you can't see
anymore of this NG!
>But, I haven't
>seen a post from him to me yet without all the above.
He doesn't need to! His little story on you was the most perfect response
he could have written.
>The facts I post should stand by themselves,
You have already screwed up big time, there were no facts involved with
anything you have written yet pertaining to guitar amps.
> And then we have the lapdogs who bark loud at his
>heels. I
You are a closet LV lapdog, admit it. But it's something else in his lap
you are looking for, no? Why do you keep going on about the lapdog thing
when all LV is putting out is the TRUTH?
Your bullshit is getting old Skippy. Bye bye now, go play somewhere else.
And please spell correctly before you slam others for misspelling.
Lord Valve
In <33eba8e3....@news.chicago.il.ameritech.net>
Lord Valve Drooleth:
Dammit, you guys are KILLIN' me! There AIN'T no pizza in Denver.
There's stuff they CALL pizza, but it's like ketchup on a cracker.
I'm an East Coast boy, ya know...(Washington, DC), and I shoveled pizza
into my gaping maw in every city on the eastern seaboard while I was on
the road back in the B3-haulin' years, and I gotta say...my favorite
was from a little joint called Pop's Italian Vineyard Room, in Wheaton,
MD., just outside of DC. (Same town that Chuck Levin's Washington
Music Center is located in. I useta work for Chuck when I was in high
school...but that's another story...) Senators and Congressmen
frequented the place, and many pizzas were spirited away by uniformed
limousine drivers at all hours of the night. (No delivery...if you
wanted one from Pop's, you hadda go get it.) They had a mean espresso,
too...served the traditional way, in little bitty cups, with a lemon
wedge on the side. Damn stuff was thick as motor oil, and one cup
would buzz you good enough to drive all the way to Cleveland. Or
wherever the next gig was... :) Hell, I'm hungry. We DO have some
killer Tex-Mex here, though. If you're ever through Denver, try the
Blue Bonnet Cafe, or the Chipotl Mexican Grill. <burp> <and worse>
This is lookin' like alt.lets.eat, huh? roflmao!
Lord Valve
oh...@lunchtime.com
CPecoraro
>That's some pretty stupid commentary...I think the original poster's
>point was that no one has all the answers and that people should never
>take for gospel what they read on usenet...
>
>IMO that's some pretty sane advice....
>
>Not to mention LV has done some slamming himself on here and he is a
>big boy and can take some back without shedding too many tears...
>
>
>
>
>
>
>
>
>
I am sorry you don't like what I have to say,
when someone who knows more about this subject comes along
with more practical experience I will take their advice, until then
I too can voice my opinion. I know LV can handle the heat.
CP
Lord Valve
In <33ec7048....@news.demon.co.uk> postm...@muffy.demon.co.uk
(Duncan Munro) writes:
(snip)
>>LV: >Only in higher power radio transmitting tubes are you likely to
see
>>LV: any
>>LV: >reverse screen current which doesn't apply here at all.
>>LV: Why mention it, then?
(snip)
>LV did not claim that reverse screen current occurs in 6L6 designs.
>He alluded to radio transmitting tubes, and the one that springs to
>mind immediately is the 4CX250.
(snip)
Lord Valve Speaketh:
Actually, the only part of the quote above that is mine is "Why mention
it, then?" Mr. Skippy was busy going off to left field at the time,
and, as usual, dropped some irrelevant information into the debate. I
admit my complete disinterest in anything which goes faster than 20KHz;
I'm a musician and an audio tech. Tom Crocker has posted a request
similar to yours, in which he asks Mr. Skippy for some hard data
regarding his contenions. You've already come up with the figure of
08 db gain reduction for a 1-ohm cathode resistor; I'm sure this
enormous figure represents total performance degradation, hence
rendering the amplifier useless to any musician who can hear the
difference. Perhaps Mr. Skippy can find such a person. Mr. Skippy is
very good at hinting about the vast knowledge he has in store for all
of us, but rather poor at posting it. The Lord awaits.
Lord Valve
Jeffrey L. Suits
On 9 Aug 1997 04:29:30 GMT, sk...@dilbert.ucdavis.edu (Skip May)
wrote:
*573 lines*of I-got-you-last.
Got to be a new asswipe record for this ng.
remove xyz to reply
Duncan Munro
On 9 Aug 1997 16:50:03 GMT, detr...@ix.netcom.com(Lord Valve) wrote:
>In <33ec7048....@news.demon.co.uk> postm...@muffy.demon.co.uk
>(Duncan Munro) writes:
>(snip)
>>>LV: >Only in higher power radio transmitting tubes are you likely to
>see
>>>LV: any
>>>LV: >reverse screen current which doesn't apply here at all.
>>>LV: Why mention it, then?
>(snip)
>>LV did not claim that reverse screen current occurs in 6L6 designs.
>>He alluded to radio transmitting tubes, and the one that springs to
>>mind immediately is the 4CX250.
>(snip)
>
>Lord Valve Speaketh:
>Actually, the only part of the quote above that is mine is "Why mention
>it, then?" Mr. Skippy was busy going off to left field at the time...
Sorry, my misquote. Is Skippy going to give me a Lapdog number?????
Duncan
--
Duncan Munro
Check out http://www.muffy.demon.co.uk/
for Homebrew guitar amps and SPICE models
Gruvmyster
Hi Skip,
Where's your shop? I'd like to see it sometime. Call me jes.curious.
Doug
--
"Think, think, think."-- Winnie-the-Pooh
You can also use mailto:dhau...@idt.net
John Kelley Brown
This thread is going nowhere, it's just a bunch of crap I have to
scroll past as I check out what's being said in this newsgroup. Most of
you guys have good information to pass along, just about everybody here
has posted at least a little bit of crap. How about a discussion on
phase inverters or transformer winding, even lawn bowling would be more
interesting.
Kelley
Lord Valve
In <33ebc0c...@news.concentric.net> rfr...@netcom.com (Robert
My cousin from NYC says 'apizza' is pronounced 'ah-PETES,' and that
'apizza' is the Italian word for 'appetizer.' (Looks suspiciously
close to 'appease,' so there may be some truth in the matter.) Anyone
know?
LV
Skip May
Lord Valve (detr...@ix.netcom.com) wrote:
Hi LV! How'er you? Let's see here...
First off, these followups are getting kind of long and the source of each
statement may become lost. Where I feel it's required, I'll mention where
the original statement came from if I know. For the best results, go back
and read my original post.
As LV chooses to continue the personal attacks, I'll no longer respond to
them in future posts and followups. They will be edited out of my replies.
Buckle up, time to roll...
: In <33E980...@thistime.thanks> Skip <nos...@thistime.thanks> wrote
: it all down in a tear-stained letter, to wit:
: >
we start the slams early LV...? doesn't do much for the facts.
: (much snippage)
: >> >First Off:
: >> >In your (Robert Hull's) previous post which adds a parallel
: resistor/diode combination
: >> in
: >> >the cathode lead to measure current by the voltage drop across the
: >> >resistor: What exactly does the diode do in circuit?
: >> LV: Nothing.
: >>
: >LV is right, it does waste about 19 cents for a good diode.
: >
: >> >Would the diode ever forward bias?
: >> LV: Nope.
: >
: >Pretty much, diodes are sometimes used to prevent certain component
: >damage when big meltdowns occur.
:
: LV: (The diode would forward bias when the tube was pulling 600 ma,
: actually. Of course, the tube would have smoked long before this, so
: my answer is substantially correct.)
As I pointed out and referenced in followups, we agree on this. Let me
take the lead and say that you also won't be adding this mod to any
amplifiers you work on?
: >>
: >> >What would this mod do to the stabilty and or tone of the amp?
: >> LV: Nothing. And I wouldn't call putting a 1-ohm resistor in
: series
: >> with the cathode a 'mod'; it's just a measurement convenience.
: >>
: >Wrong LV, when Leo Fender sold Fender to CBS, the engineers were
: allowed
: >to place these type of mods in the amps to "tame them down", or make
: >them more reliable. This is usually refered to as the black face to
: >silver/white face era. Ask any vintage dealer which amp is worth more.
: >Also tell us how the bias was set at the factory...? Although this mod
: >is a simple one, I wouldn't want it in my amplifier. Carbon resistors
: >change value with age, metal film resistors have reactance even at low
: >values. Be your own judge folks...
: LV: SKIPPY!!! You're so far off-base on this, folks are gonna wonder
: if you've ever even SEEN a guitar amp!! ROFL!! PLEASE...tell us how a
: ONE OHM resistor in series with the cathode of a guitar-amplifier power
: tube will be seen as anything other than a straight wire by the tube.
Two points here. As I mentioned before. This is a mod I wouldn't do
because it's not required. It takes away from the vintage/originality
of the amp and would detract from it's resale value in some vintage
stores (if you wanted to resale it). This is a small issue for some and a
big issue for others, pick your spot.
Second, most any tech worth his/her salt should have no problem setting
bias without parts additions. Remember the factory did it, you should also
be able to.
The sonic difference might be minor, but it's there. The degeneration
(reduction in circuit gain) added may be minor at DC, the AC gain mightbe
an entirely different story. For those of you reading this followup with
less experience, thats why capacitors are often in parallel with resistors
in the cathode and other places, to increase the AC gain of the stage.
The amount degeneration would depend on the quality of the resistor and
makeup.
: Huh? Pretty please? Fender cathode bias resistors were 150 ohm,
: 7-watt jobbies...and those amps were a combination of fixed and cathode
: bias, to boot. (See the Dual Showman Reverb AB568 schematic for a
: typical setup.
I believe these were original parts and not "guru ad on's", am I right?
Handy to have for measurements if the factory put them in.
A nice mod to add in with the diodes if your Robert "ampman" Hull.
: You..uh...you DO know how to read a schematic, right?
yep, got a few here also... onward
: And you have a few? I mean...for GUITAR amps, yes? Just checkin'...)
: Now, for a fixed-bias design, we're looking at a potential difference
: between the cathode and the grid of -52 volts (or thereabouts) at
: idle...
Which type tube? I wouldn't take the above as gospel for all fixed bias
designs and tubes. These are your unedited word here... If your
referencing the Fender mentioned above? why? How did we go from 1 ohm
resistor mods to this Fender? What's the point LV? Technoblather alert
folks! Did we go to an amp with original factory installed resistors from
one which had none in the original design?
:I realize that you know so VERY much more than all the rest of
: us on this NG, but...Skippy, ol' pal...
Where did I say that LV? Off topic slam, a diversion tatic.
: are you gonna hip us as to how
: in the hell the 30-40 MILLIVOLTS that the 1-ohm resistor will subtract
: from the cathode-grid difference voltage is gonna do anything audible,
: or in any way at all affect the performance of the amplifier? (I
Yep, the preformance of the amplifier's price might go down 3dB at the
store where you might want to trade it in. The 1-ohm resistor which I feel
is not required takes time to put in. How much an hour do you charge? Do
you have a min charge. Do you charge for the part? If you were Robert,
you'd be adding in the diode secret mod also?
It's a mod which changes the stage gain LV! Even a small amount would
change the potential acoustic feedback levels, some musicians use this and
other sounds to create music. I think James Marshall Hendrix was one....
: promise not to hold my breath, son...)
: >
breath please, we wouldn't want you to burst.
: >> >Most of all, what's wrong with this method of measuring bias?
## >> LV: I know what you'd like me to say...that it doesn't take screen
## >> current into account. OK, it doesn't. So what? A couple of
: milliamps
: >> is negligible...we're not looking for laboratory accuracy or trying
: to
: >> achieve some absolute value here; we're just looking for the best
: tone.
: >> The bias point necessary to achieve that tone may fall anywhere
: within
: >> (or even outside, if lower) the published (or actual) specs for the
: >> tube. As long as you're not crowding the high end of the current
: spec,
: >> this is a non-issue. Besides, you would tend to err on the LOW side
: of
: >> the spec, since the screen current would be ADDED to the cathode
: >> current with this method.
: >>
: >Here we go with foot in mouth again for LV. Explain to me LV where
: the
: >path for this screen current goes if not through the cathode?
: LV: Who said it DIDN'T go through the cathode? Where in the hell ELSE
: would it come from! Skippy, do you need glasses? Or is this a reading
: comprehension thing...hmmm...
Might be, your first post with the statement above (marked by me with the
double ## signs above) didn't make sense to me. That's why I asked you to
repost your position. Something about ..."that it doesn't take screen
current into account. OK, it doesn't." which appears to me to be the
reverse of your other statement(s).
:
: You way off base here.
: LV: I is? (Your grammar, but, hell...I'm flexible...)
Fast typing errors, you've made a few also but it's not worth worrying
about. Anything your not clear about, I'm happy to repost, onward.
: The cathode contains the sum of the grids and the anode.
: LV: Duh. Thanks, prof.
Slam time...
You had not made a followup post when I mentioned the above fact. Call me
reactionary, but your statements above ## are wrong. Even if it's a small
amount of current.
: >Only in higher power radio transmitting tubes are you likely to see
: any
: >reverse screen current which doesn't apply here at all.
: LV: Why mention it, then?
To make a blanket statement about tube screen current would be wrong.
Under certain operating conditions and designs, reverse screen current
happens in a 6L6. But you knew that LV, care to tell us any examples? What
if any effects it may cause?
: >Your last line about "added to the cathode current" may be your only
: >way to explain your way out of this one... please do so.
My request for information about the ## statements above, simple enough.
: LV: What's to explain? From what I've read elsewhere on this thread,
: EVERYONE ELSE knew exactly what I was talking about. What I said was
Well spank me, I didn't read it well enough? I was under the impression
the top and bottom of the original paragraph above are reverse statements.
: that the screen current would induce a small error into the quiescent
: current measurement. Is this a mystery to you for some reason? If we
: measure 35 ma (35 mv) across the 1-ohm cathode resistor, and 2 ma of
: that is screen current, then it stands to reason that the remaining 33
: ma is plate current, yes? C'mon, Skippy...you're gonna hafta do a lot
: better than this...
Somehow the above numbers didn't make it to your original post? Had you
given a straightforward example the first time, I might not have asked for
a second try. Maybe my newsgroup reader is leaving out the technical
stuff in favour of technoblather.
: (more snippage)
I agree here, much more snippage in future posts and followups...
:
: >> LV: Personally, I like 'em on the hot side. Power tubes are (or
: >> should be) designed to run at the proper temperature WITHOUT
: additional
: >> cooling, as long as specs are not exceeded. Tubes designed to burn
: >> base-down which are being operated base-up could possibly derive
: some
: >> slight additional longevity from fan-cooling, but this would be more
: >> beneficial to the plastic base than to the metal parts inside the
: tube.
: >
: >There are other factors which come into play here LV. All tubes derive
: >benefits by cooling of the base and external anode metal pins.
: LV: So? Nearly impossible with 'small' tubes like guitar-amp power
: tubes. Non-issue.
Not really, are not the tube socket pins metal and in direct contact with
the tube pins. Doesnt' heat conduct through metal well? Wouldn't any
amount of air moving over/around/past (pick one) these socket pins pickup
the heat much better than blowing air past the glass which is an
insulator? Facts or fiction? Can Svetlana, Eimac be printing bad
information in their data sheets? (Svetlana has a great web page)
Wouldn't a well designed below chassis air system venting up
through/around/past the tube socket/pins and past the glass envelope big a
big help? Did Soldano make useless holes around the tube base in the Hot
Rod 50 amp I saw last weekend?
Your might learn something soon LV...
: Air
: >movement around the glass is fine, but no where near as effective as
: air
: >flowing around the metal pins. This would be a great place to
: establish
: >this fact. Have a look at large tube applications.
: LV: Why? There is very little extra real-estate in a guitar amp,
: which must be small enough and light enough for a musician (you
: remember those dudes, right, Skippy? They're the folks who actually
: USE this gear...) to move it from gig to gig. Please tell us how you
: are going to install some cumbersome pin-cooling system in a Deluxe.
: We're not talking 50KW radio-station finals here, dude...try to stay on
: topic. "GUITAR" amplifiers, ok?
: (snip)
Fun time...!
OK, let's do it. Remember that we live in the 90's now LV. There are small
fans and blowers which easily fit in tight spaces. Even your local Radio
Shack has reduced size fans which fit inside tight areas. Best of all,
remember those little fans on your CPU chips? They are low noise and can
be installed below chassis without much effort and zero holes and circuit
mod's. In an addtional posts away from here I'll be happy to detail this
most wonderfull thing.
For those of you leaving to buy the fans now, be sure to buy only good
quality ball bearing units. More on that later...
All this nice air makes those LCR electrolytic caps real happy. They like
to dry out with heat.
: >
: >> As far as the glass goes...if it were pure, it probably wouldn't
: heat
: >> up much at all. Most of the heat which leaves a tube does so as
: >> infra-red radiation, and it goes through the glass like it wasn't
: even
: >> there. Only impurities in the glass (and dirt on the surface, which
: is
: >> why I always hit the tubes with some Windex when I'm doing
: maintenance)
: >> can absorb this radiation, thus gradually raising the temperature of
: >> the bulb. (Some heat is added by direct conduction where the wires
: >> exit the bulb, too.) Heat from the bulb is re-radiated (at a much
: >> slower rate) at a different frequency of IR. (Lower, I think...)
: >
: >Well, you got your foot in your mouth again over the above, but the
: >addtional posts set your straight. All you others should go back to
: the
: >original thread to read the information others followed up with. It's
: >on the money...
: LV: Yes, it is...however, in order to be EXACTLY sure I'm "wrong",
: you'll have to tell us in which part of the IR spectrum the bulk of the
: heat radiated by the plates lies...because if it's in a portion of the
: spectrum to which glass is relatively transparent, then I'm more
: "right" than you are. Mexican standoff, si?
: (snip)
Why LV? I never brought it up, can't do a lot to change the facts and
don't care much that you made the mistake in the first place. That's why I
left it out of the followup posts. Others can go back and see your "foot
in mouth". Glass is a better insulator vs metal base pins where my
attention is directed.
I'm not going to board the ship when it's sinking around you.
Bail! Bail!
:
: >> >should have your bias checked? What would this change be?
: >
: >> LV: I reckon that as the cathode degrades over time, we'd want to
: >> lower the bias voltage slightly to suck them trons a leetle bit
: harder.
: >> This would increase the current back up to the optimal point.
: >> Remember, though...we're lookin' for TONE here, so I'd only adjust
: the
: >> bias if the musician complains about the way the amp sounds.
: >> >
: >
: >You might do this LV, I wouldn't. Have you ever measured the
: distortion
: >that occurs when you move the bias to a non linear portion of the
: >operating curve?
: LV: Have you ever asked the guy who owns the amp if he LIKES it that
: way? As long as the tube is not being damaged...who will give
: 000000091 of a rodent's posterior about 'non-linear' operation?
When they bring you an amplifier to fix, don't they ask you to make it
right? ... or do they ask you to make it "almost right". Didn't they
bring you the amplifier because it needed to sound better or be fixed to
sound better. I guess "almost" is good enough for your shop.
Only
: you, Skippy, and that pack of anal wankeroid magic-wires enthusiasts
: over on RAT. I suspect.
:
Slam alert, watch for possible technoblather...
: The only real fix is to replace an old tube or increase
: >the heater voltage (with the coresponding decrease in lifespan), not
: >practical in most amplifiers but often done in higher power tube
: >equipment. Leave the bias set in the linear operating area where it
: >belongs.
: LV: (See above.)
: >
or you could take it to the guy who fixes it almost good enough...
Still haven't seen you mention anything about tube life vs heater voltage,
a major player in any amplifier. I guess I might be doing that later.
: >> >An amplifier with the bias set wrong could have higher
: idle/operating
: >> >current and run hoter within it's ratings , but the amount of power
: >> the
: >> >tube can handle, remains the same. If the tubes are biased wrong
: but
: >> still
: >> >within their ratings, how will tube life be greatly reduced,
: Robert?
: >> >Anyone? Details please?
: >
: >> LV: It wouldn't.
: >>
: >Well, he got this one right...
: LV: Jeez...Skippy's getting better at reading comprehension...
: >
thanks LV your a light in the fog...
:
: >> LV: The 'best' way to bias an amp is the one that makes it sound
: the
: >> way the musician likes it to sound. There are several different
: >
: >Even if it's not right, keeps the customer comming back. Right or
: wrong
: >that seems to be the way of life...
: LV: Skippy...the customer keeps coming back (and has done so for
: nearly 30 years now) because...I realize this may be a difficult
: concept for ya, son, but bear with me a minute, here...HIS SHIT KICKS
: ASS when I'm through working on it. (Imagine that...satisfied
: customers! See? I TOLD ya this would be difficult for
: ya...capitalism, no? More on THAT subject later...)
: >
Now we're on to a specific examples here, OK ... I can dig it, can you? Do
you ask him if almost good enough is fine with him? Well, yes I guess you
do.
I'm glad his amp works almost as well as it could, imagine the concept of
it working the best it could. It might just really "kick ass", "better".
You might mention in your next flame if you've' been setting his amp up
almost good enough for the entire 30 years? Also if you offered him the
option of having it sound the best it could? Maybe the diode mod is
comming soon, they do nothing but hey... he's still be a satified
customer and his amp would sound good...
: >> ways...cathode resistor, plate resistor (for you accuracy freaks),
: >> output transformer primary shunt method (scary, and not all meters
: can
: >> do it), the crossover notch method, the 'by ear' method (which
: usually
: >> starts out with one of the other methods to get into the ballpark,
: and
: >> finishes up with some listening/diddling/listening/diddling action),
: >> and the harmonic distortion meter method. I've used 'em ALL at one
: >> time or another. I routinely use the crossover notch method on
: older
: >> Marshalls; I seem to be able to achieve what my customers want on
: those
: >> amps with a scope and my eyeballs.
: >
: >Not much information here, just bragging.
: LV: I'm reminded of a quote attributed to Babe Ruth: "It ain't
: braggin', if ya can DO it." ('Nuff said.)
almost perfect?
:
We may be able to take this forward folks. I'm aware of at least two
methods to shunt test a transformer. As I mentioned, one I don't like as
it tends to strain the transformer the other is very different and prob
LV's version. He wasn't specific or may not know the other method..
After I establish the actual one LV's talking about, I'll try to bring the
other to light in another post as time allows. Feel free to take me to
task about it if you don't agree...
There's a chance we may not have a difference of opinion here, just think
about the possiblities?
: But setting an amp is a
: >compromise. I always use a scope and a meter. I've never seen a
: perfect
: >amp but the scope will help me get it to the best place it's gonna be.
Yep, I use it, the meter, a load, a speaker and many other tools and test
equipment to establish how well the amps' working. Like to know what's
going on inside.
: LV: WOW! This deserves an entire additional post! Check for
: "SKIPPY'S FULLA CRAP, Part Two..."
: >
How about a label the others can read without a slam alert label.
: > For Fenders, I like the cathode
: >> resistor method; many times, I'll finish up by ear, if the customer
: is
: >> in the shop at the time. (Sometimes, I gotta do my own pickin' and,
: >> well...I, er...play the guitar like you'd imagine an organist would.
: >> Badly!!) Most Ampegs aren't adjustable, so I usually do a
: transformer
: >> shunt check to make sure things are in the ballpark. A peek at the
: >> quiescent current draw for the entire amp is in order here, also. I
:
: >Buzz words,
: LV: Hmmm...exactly which words started you buzzing? Are you sure
: you're not suffering from some sort of electroencephalitic oscillation,
: Skippy?
: >
let me rephrase this, technoblather. Do people care how bad your picking
is LV? If you can't hear the amp with your ears, it prob still needs work.
...gotta have some fun, this is really stiff stuff... you don't seem to
have much of a sense of humor.
: > I don't like transformer shunt checks.
: They tend to place a
: >strain on older transformers. I've seen two go away in a guys shop
: >during a shunt test.
: LV: Lord Valve will watch with great interest while Skippy explains to
: the entire Usenet how REMOVING the current from one leg of the output
: tranny's primary will "strain" it.
As I mentioned above, there's another shunt test you might not know about.
Since you wern't specific about which on you were doing, you may not even
know about the other. Care to tell us if you do? It's the one I (and
others) prefer to avoid in vintage equipment. It's hard to get original
transformers at a good price. But you could sell them another...!
: The Lord will also await posts from
: the other techs (sorry, Skipper...you don't qualify for this one) on
: this NG as to exactly how many trannies have croaked from this
: practice.
:
there's that "py" again... should I throw out the diversion warning again?
Na.. I'm a gambler, let's go on.
(major snip)
:
: I don't use a spell check program.
: LV: No kiddin'. Neither do I, Skipper...see the Babe Ruth quote
: again, if you require enlightenment on this.
: (snip)
I went down the hall and found the Dictionary for use at home, you'll have
to suffer till I get back there.
: >I have nothing to hide or sell on the newsgroup.
: >You may have nothing to hide, but your always trying to sell us
: >something.
: LV: EGAD!!! Skippy's bummin' out over Capitalism. I TOL' y'all he
: was one o' them Ivory Tower Lefties, didn't I? I got it, now...he's a
: Clintonista...you know...those .edu-cats who carry around a copy of the
: Little Red Book in their hip pockets, in lieu of a wallet? You are
: ABSOTIVELY, POSOFUGGINLUTELY RIGHT, Skippy. I own a music store. I
: sell stuff ALL DAY LONG, and if I can figure out a way to do it all
: NIGHT long too, I'm gonna do it.
Well, we got to the above before the diversion tatics kicked in. Oh well,
let's talk...
I don't have a problem with you or your store. You have a problem with
not being able to take the heat and use names to try and put other people
down when your feel threatened. It doesn't take you or others very far.
Yep, from what I understand, it only took you thirty years to get
the formal store open, congrads' there. This is your first or second year
as a formal store owner? Paying retail rent? having to sell lots of
products and amplifier work/mods to keep your doors open?
Occasionally, I post a "LORD VALVE'S
: SPAM LIST" article, where I invite people to REQUEST advertisements via
: e-mail from me.
I never asked to be on your spam list and I receive them. Am I one of the
663 or just in a special group. Are there others in your special group?
Will I not be booted off the list?
Much more off topic diversion stuff to follow. This doesn't really do much
but pump your ego back up and get a free plug out. Smoke alert...
To date, (8/8/97) 663 people have requested this.
: Many of these people have bought tubes, speakers, repair parts, etc.
: from me. I invite any one of them who has been in ANY way dissatisfied
: with anything they ever bought from me to snip this portion of the
: thread, re-name it "LORD VALVE RIPPED ME OFF", and post the details.
See the free plug above. Remember, New Sensor in NY has much better prices
on tubes and some of the same parts. See their web page and ask for their
free catalog. I've been very happy with every purchase throught the years.
: Capitalism is a two-way street, Skippy...BOTH parties must be satisfied
: with the transaction for it to survive. (I realize that this is a
: startling concept, and not seen all that often on America's campuses.
: Go figure.)
Diversion alert here.
Where in any of my posts do we talk about your business except where you
bring it up? Why would it have anything to do with Roberts diodes?
Cutting holes in your amplifier case to add a fan (not my choice)? Last
but not least, use it examples of people who've gone home with extra
resistors in their amplifiers because you can't do what any good tech
or the the factory does?
: Lord Valve :
: spa...@njammin.com
If we take this further, you've got to drop the excess bagage LV, the bad
language and personal slams and stick to the facts. I'm happy to have any
civil debate or talk technical issues with you and others as I have time.
You and I might both learn something... right? But remember, I might not
always agree with you and I'll post it out in the open with what
information I have to use for support of my point.
Just ask the Lapdogs to stay at home or join in with "the facts man."
Cheers
Skip May
nosp...@juno.com
Ned Carlson
sk...@dilbert.ucdavis.edu (Skip May) wrote:
>First off, these followups are getting kind of long
Ned Sez:
Kinda long! No kidding!
They're longer than chainletter spams!
>and the source of each
>statement may become lost. Where I feel it's required, I'll mention where
>the original statement came from if I know. For the best results, go back
>and read my original post.
Ned Sez:
Ever considered crossposting to rec.audio.tubes?
C'mon, I know we'd like to how the EE's over there would respond
to your posts. OTOH, many of them post from domains like nasa.gov,
hp.com, tek.com, mot.com, and so forth, one which might be
someday be your future employer, so be careful, as dubbing them with
monikers like "lapdog" might be inadvisable.
>: LV: SKIPPY!!! You're so far off-base on this, folks are gonna wonder
>: if you've ever even SEEN a guitar amp!! ROFL!! PLEASE...tell us how a
>: ONE OHM resistor in series with the cathode of a guitar-amplifier power
>: tube will be seen as anything other than a straight wire by the tube.
>
>Two points here. As I mentioned before. This is a mod I wouldn't do
>because it's not required. It takes away from the vintage/originality
>of the amp and would detract from it's resale value in some vintage
>stores (if you wanted to resale it). This is a small issue for some and a
>big issue for others, pick your spot.
>Second, most any tech worth his/her salt should have no problem setting
>bias without parts additions. Remember the factory did it, you should also
>be able to.
>The sonic difference might be minor, but it's there. The degeneration
>(reduction in circuit gain) added may be minor at DC, the AC gain mightbe
>an entirely different story. For those of you reading this followup with
>less experience, thats why capacitors are often in parallel with resistors
>in the cathode and other places, to increase the AC gain of the stage.
>The amount degeneration would depend on the quality of the resistor and
>makeup.
Ned Sez:
I'd think differences in tubes, biasing, even the typical variations
found in output transformers would overshadow any diff made by
1 ohm resistors by a bunch.
>: are you gonna hip us as to how
>: in the hell the 30-40 MILLIVOLTS that the 1-ohm resistor will subtract
>: from the cathode-grid difference voltage is gonna do anything audible,
>: or in any way at all affect the performance of the amplifier? (I
>
>Yep, the preformance of the amplifier's price might go down 3dB at the
>store where you might want to trade it in. The 1-ohm resistor which I feel
Ned Sez:
Ya know, we've sold a few Fenders here, I don't recall any people
that bought 'em for real use, ever even looking under the chassis
to see if there were 1 ohm resistors installed. They just played it in
the store. Never saw any inkling that 1 ohm resistors would make a
diff in the price.
Maybe some other folks have different experiences, but many of the
folks we deal hardly fell of a turnip truck. If there was an issue
with resale value, I find it hard to believe either me or my partner
wouldn't have heard about it.
>is not required takes time to put in. How much an hour do you charge? Do
>you have a min charge. Do you charge for the part? If you were Robert,
>you'd be adding in the diode secret mod also?
Ned Sez:
It only takes a minute or two. There wouldn't be any additional
charge to speak of.
>It's a mod which changes the stage gain LV! Even a small amount would
>change the potential acoustic feedback levels, some musicians use this and
>other sounds to create music. I think James Marshall Hendrix was one....
Ned Sez:
I think changing from Sylvanias to Sovteks, for example, or 12AT7's
wearing out, would cause a greater diff in open loop gain than a
a 1 ohm resistor would.
Heck, the tolerance in the screen grid resistors would make
more diff...the originals were 10%, weren't they?
>To make a blanket statement about tube screen current would be wrong.
>Under certain operating conditions and designs, reverse screen current
>happens in a 6L6. But you knew that LV, care to tell us any examples? What
>if any effects it may cause?
Ned Sez:
Measuring bias current at idle, reverse screen current is a nonissue
in this case. An RF amp is a different issue.
Heck, even Magic Wires pieces like Conrad Johnson and ARC
don't even consider it, they all set bias by cathode current.
Heck, Dynaco does the same thing, but with (gasp) a 15.6 ohm
resistor!
If we're talking recieving, not transmitter tubes,
then in TV sweep tubes reverse screen current
may be a consideration.
If reverse screen current was an issue, Fenders might have
screen pass regulators. In a TV (yup, 6L6's were used in TV's at one
time, as was it's brother 6BG6-G),the G3 might have been run at +20
volts to counteract the problem, but 6L6's don't have
separate pins for the beam-forming plates, nor were ever used
as sweep tubes in 27" color TV sets.
Somehow I don't get the idea that Fender & Marshall
employees lost any sleep worrying about reverse screen current.
>Not really, are not the tube socket pins metal and in direct contact with
>the tube pins. Doesnt' heat conduct through metal well? Wouldn't any
>amount of air moving over/around/past (pick one) these socket pins pickup
>the heat much better than blowing air past the glass which is an
>insulator? Facts or fiction? Can Svetlana, Eimac be printing bad
>information in their data sheets? (Svetlana has a great web page)
Ned Sez:
On glass tubes at least, it is not advisible heat to try to
dissipate heat thru the base pins.
Case #1: RCA, Altec, and Ampeg all tried using 6146B tubes
in audio amplifiers. All of them later issued refits for 6550, too.
The reason, mainly, was that the short stature of the 6146
made too much heat dissipate through the base, which then
became loose from the heat. Once an Ampeg player brought
me the bulb from a 6146: the base glue had evaporated, and the
solder had melted out of the pins. He tried to pull the tube
out & the base stuck in the amp..bulb came out.
Case#2: Take a look at an Eimac 3-500Z, for example.
It has a BIG glass bulb, and the pins are long ways from
the anode.
A big air system chimney covers it, too..the idea is to dissipate
the heat off the glass before it gets to the pins and causes
trouble.
I believe that applies to ceramic external-anode tubes as well, it's
been awhile since I've peddled one, but I recall what happens when
they overheat is that the ceramic seals crack. Thus the idea is to
keep heat away from any ceramic/metal or glass metal seals,
not try to disspiate heat through them.
As well as upside down tubes in Fenders are concerned,
well, rock n' roll ain't rocket science. They're not 4CX35,000,
and carrying a spare pair won't require hiring extra roadies...
>: >You might do this LV, I wouldn't. Have you ever measured the
>: distortion
>: >that occurs when you move the bias to a non linear portion of the
>: >operating curve?
>When they bring you an amplifier to fix, don't they ask you to make it
>right? ... or do they ask you to make it "almost right". Didn't they
>bring you the amplifier because it needed to sound better or be fixed to
>sound better. I guess "almost" is good enough for your shop.
Ned Sez:
Skip, I think you missed the point here. A guitar amp isn't just
an audio amp, it's an extension of a musical instrument,
and for distortion purposes they are treated as such.
The question isn't avoiding distortion, unless the
player wants a super clean sounding amp.
The idea is to add the harmonics that give the instrument
the sound the player wants.
Musical instruments aren't supposed to be linear,
or without harmonics.
If all we wanted was perfect
sine waves, we'd all listen to tuning forks
and audio oscillators.
>or you could take it to the guy who fixes it almost good enough...
>Still haven't seen you mention anything about tube life vs heater voltage,
>a major player in any amplifier. I guess I might be doing that later.
Don't bring that up, if them gurus get any ideas, they be selling
filament voltage jackup mods to make the amp sound hotter..
>
>: >> >An amplifier with the bias set wrong could have higher
>: idle/operating
>: >> >current and run hoter within it's ratings , but the amount of power
>: >> the
>: >> >tube can handle, remains the same. If the tubes are biased wrong
>: but
>: >> still
>: >> >within their ratings, how will tube life be greatly reduced,
Actually, cooler tubes will last longer.
There have been studies on that.
But that's not the point, the point is to get the tone right,
within acceptable parameters.
If some wants to run the tubes hot, and they think
it sounds better, fine, they can carry a spare pair.
It's their amp, their tone & their money.
Indy car tires would last a lot longer if would last a lot
longer if they weren't pushed so hard,
but the point of car racing is to win, not save tires...
Marko
That's some pretty stupid commentary...I think the original poster's
point was that no one has all the answers and that people should never
take for gospel what they read on usenet...
IMO that's some pretty sane advice....
Not to mention LV has done some slamming himself on here and he is a
big boy and can take some back without shedding too many tears...
This brings up a very interesting point.
From what I've seen, LV has TRULY helped many, many people, via this
board. This is really wonderful, and I salute him for this.
There also seems to be a 'Heckle + Jive' personality that is unecessarily
rude, crude, hurtful to others without knowing them, etc...whatever, that
spews forth overshadowing the factual points he always tries to make.
So one person comes onto this board, and LV and he start into it.
In an amazing display of Mob Mentality, several of the regulars, who hang
out at the park with LV often, decide to simply attack the one person
with insults.
However, for Everyone to technically answer this one person's questions
directed at LV, is just Way too easy for LV!... Like LV is weak, feeble
or something like that, and needs everyone to technically answer for him!
TIME to See Skippy and LV thumbwrestle one-on-one, so we can get to the
meat of the matter.
Marko
Mark L.
Skip!
Actually, I am independent..., and I am looking forward to a One-on-One
between you and Fat Valve,...uh...er...Lord
Willie,....er....BabaGeeRabaGee Guru...uh.....Whoever he is....so the
issues that bothered you so much about him can be factually discussed...
You are a tough one to hang in there with the mob scene.
I'd rather see you guys go toe-to-toe without distractions to find out
what the big deal is. You challenge his knowledge base, business
enterprise, and a whole(not to be confused with A-hole) slew of people
decide to technically answer for him.
Hey!!!!....Segregated Menbers of the Alt.Amp group........
Back Off and let these two talk for themselves. I want to see it
Mark L.
Anwari
Jeremy Epstein wrote:
> The best pizza made is available in
> New Haven, CT, bar none. There are three pizzerias on ONE STREET, within
> three blocks, better than any in all of NY (that I've tried, caveat
> there) which I will list for your edification :
That is true. Best pizza made anywhere. Anybody who says theirs is
better just hasn't been to New Haven. BTW, it's just about the only
thing good about the town <G>.
> Pepe's, The Spot (Pepe's second string, still better than anywhere I've
> ever been outside of New Haven,) and Sally's. Modern is not on the same
> block but makes a worldclass pie nonetheless. And they spell it the old
> way, "apizza," which I kinda like.
Modern is in the same "league," but nowhere near as good as Sally's or
Pepe's. Nina's in Branford is better than Modern. Abate's is almost as
good as Modern.
Kap'n
Ned Carlson
John Kelley Brown <ledb...@tdl.com> wrote:
>has posted at least a little bit of crap. How about a discussion on
>phase inverters or transformer winding, even lawn bowling would be more
>interesting.
How about pizza?
John Byrns
In article <33ee0375....@news.chicago.il.ameritech.net>,
postm...@triodeel.com wrote:
> John Kelley Brown <ledb...@tdl.com> wrote:
>
>
> >has posted at least a little bit of crap. How about a discussion on
> >phase inverters or transformer winding, even lawn bowling would be more
> >interesting.
OK, Thin Crust or Deep Dish? I know that's a dumb question, maybe we need
two threads, so there's not too much flaming.
Regards,
John Byrns
Ned Carlson
jby...@enteract.com (John Byrns) wrote:
>OK, Thin Crust or Deep Dish? I know that's a dumb question, maybe we need
>two threads, so there's not too much flaming.
John:
Try doing a DejaNews Power Search on "pizza" in "alt.guitar.amps"
I'm not sure you want want to get into it, it's a pretty heavy (and
pretty funny, too) subject!
Me, I'm an enchilada (or fill in your favorite Mexican food here)
man,(Thai is swell, too) my wife doesn't even know how to make pizza.
(OTOH, ever had chiles rellenos made with *red* chiles? Yum!
BTW, those all-you-can-eat Indian buffets on Devon Ave gotta be
dang near the best deal in town..)
So I dropped out of the discussion.
From what I can gather, New Haven CT, supposedly has the best
pizza in the country. Brooklyn, Champaign, IL (Papa Del's),
and Davis, CA (can't remember where) are right up there.
Chicaguh hasn't had a mention yet..note there is quite a
variety here...somebody will speak up for da Winny Ciddy yet,
I'd bet...
Note "Chicago Deep Dish Pizza" was invented by a Texan.
Says so right on the wall of Pizzeria Uno.
NathanW|RiverWest Entertainment
> OK how about Home Run Inn on the west side of Chicago for the best 'Vintage' Pizza :-)
Yep I heard they left them out a long time.....8>)
--
Regards
NathanW|RiverWest Entertainment
Remove the ** from address to e-mail
Scott Hinman
Teleologist wrote:
>
>
> OK how about Home Run Inn on the west side of Chicago for the best 'Vintage'
> Pizza :-)
--
You ever do your own home-made vintage pizza? Mine always
turns out black-faced.
.*°*€°.- Remove the ?'s to reply-.*°*€°.
Skip
Ned Carlson wrote:
> Ever considered crossposting to rec.audio.tubes?
I have posted to rec.audio.tubes, thanks.
> C'mon, I know we'd like to how the EE's over there would respond
> to your posts. OTOH, many of them post from domains like nasa.gov,
> hp.com, tek.com, mot.com, and so forth, one which might be
> someday be your future employer, so be careful, as dubbing them with
> monikers like "lapdog" might be inadvisable.
I'd also not want to post a reply with a slam on their domain name as a
base. It doesn't prove much. I've met some really nice people there and
over here. Some lapdogs and gassed up guru's also.
> Ned Sez:
>
> I'd think differences in tubes, biasing, even the typical variations
> found in output transformers would overshadow any diff made by
> 1 ohm resistors by a bunch.
>
Ned, your prob right. I have no problem with your choice to add anything
you want inside your amplifier. All the above would make every tube amp
different. Some better than others...
> Ned Sez:
>
> Ya know, we've sold a few Fenders here, I don't recall any people
> that bought 'em for real use, ever even looking under the chassis
> to see if there were 1 ohm resistors installed. They just played it in
> the store. Never saw any inkling that 1 ohm resistors would make a
> diff in the price.
>
I don't have a problem with your store's business. If you were selling
vintage equipment at top dollar resale prices and Aspin Pittman or
Michael Doyle walked in. They would be much happier to buy the Gibson,
Marshall or Fender amplifier in original condition (less the mod). Take
a look at their books where they often tout the amplifier as being in
original condition. For a better opinion seperate from mine, call Black
Market Music in the LA or SF Bay Area, Real Guitars in SF, Univibe in
Berkley or Walnut Creek, CA or Mannys. Ask them which way the vintage or
high dollare tube amplifier is prefered.
> Maybe some other folks have different experiences, but many of the
> folks we deal hardly fell of a turnip truck. If there was an issue
> with resale value, I find it hard to believe either me or my partner
> wouldn't have heard about it.
>
If you've ever gone searching for a rare vintage amp, you know the
equation: Original/unmodified=high resale value
non-original/modified=less money
> Ned Sez:
>
> It only takes a minute or two. There wouldn't be any additional
> charge to speak of.
>
Ned, if this were a vintage or high dollar amplifier, would the
technician take the time to explain that amplifier mod changes the
resale value, especially if he didn't know how to set the bias without
doing the mod?
The technician in another shop doing the same type of work without the
mod makes the customers amp work just as well without hurting the resale
value?
> >It's a mod which changes the stage gain LV! Even a small amount would
> >change the potential acoustic feedback levels, some musicians use this and
> >other sounds to create music. I think James Marshall Hendrix was one....
>
> Ned Sez:
>
> I think changing from Sylvanias to Sovteks, for example, or 12AT7's
> wearing out, would cause a greater diff in open loop gain than a
> a 1 ohm resistor would.
Could be, replacing with equiv tubes in a vintage/high dollar amplifier
is not considered a mod with most people, adding resistors would.
> Heck, the tolerance in the screen grid resistors would make
> more diff...the originals were 10%, weren't they?
>
Depends on the mfgr and year/model. The tolerances ran all over the
place in some models. Some mfgrs were better about it.
I've had people want the original type carbon resistors located and
installed to keep the amp sounding original during a repair. These guys
think that metal film sounds different, not bad, just different.
> Ned Sez:
>
> Measuring bias current at idle, reverse screen current is a nonissue
> in this case. An RF amp is a different issue.
Yep, your right.
Bias voltage controls cathode current for the AB1 operation of a generic
audio amplifier circuit. Your sentence above is not clear to me.
If your a pure at heart, reverse screen current would be considered in
the design if you wanted to go that far. A neat science unto itself.
The power gains are often much larger for RF amplifiers. Most guitar
amps use tube types where it's not a problem.
> Heck, even Magic Wires pieces like Conrad Johnson and ARC
> don't even consider it, they all set bias by cathode current.
> Heck, Dynaco does the same thing, but with (gasp) a 15.6 ohm
> resistor!
Is it there in the original design? No problem then, use it. If you
owned an ST-70 audio amplifier, you might be a member of the original
school of virgin ST-70 amplifiers. Or, you might be a member of the
school which did a complete retrofit of the input section. Each month at
Livermore, CA the two groups haggle over the price of this amp based on
the condition, price, mods... on and on. The modification group has
learned that selling the amplifier with a bag of the original parts that
were removed makes the price much higher.
> If we're talking recieving, not transmitter tubes,
> then in TV sweep tubes reverse screen current
> may be a consideration.
>
> If reverse screen current was an issue, Fenders might have
> screen pass regulators. In a TV (yup, 6L6's were used in TV's at one
> time, as was it's brother 6BG6-G),the G3 might have been run at +20
> volts to counteract the problem, but 6L6's don't have
> separate pins for the beam-forming plates, nor were ever used
> as sweep tubes in 27" color TV sets.
Your right, it's not considered a big issue as it's an easy problem to
design out in circuits where it might be a problem.
The mention of sweep tubes was not from me, but it's a subject which
holds my interest at the moment.
We have to keep two points in mind here, what's practical and what
isn't.
Mfgrs didn't bother with screen regulation it's expensive and not
required for the consumer guitar amplifier market.
>
> Somehow I don't get the idea that Fender & Marshall
> employees lost any sleep worrying about reverse screen current.
>
Yep, it was dealt with by selection of tubes and circuit design. Ampeg
and some other mfgrs had some fun with it for a time from what I read.
One of a few serious problems using 6146 tubes in their early designs.
The proper addition of a screen grid "bleeder" resistor pretty much does
away with the problem.
> >Not really, are not the tube socket pins metal and in direct contact with
> >the tube pins. Doesnt' heat conduct through metal well? Wouldn't any
> >amount of air moving over/around/past (pick one) these socket pins pickup
> >the heat much better than blowing air past the glass which is an
> >insulator? Facts or fiction? Can Svetlana, Eimac be printing bad
> >information in their data sheets? (Svetlana has a great web page)
>
> Ned Sez:
>
> On glass tubes at least, it is not advisible heat to try to
> dissipate heat thru the base pins.
I don't agree, in fact it's much more efficient to remove unwanted heat
with airflow past the base and ext anode (if used) pins. As the power
level goes up, it becomes the only way to cool the tube and stay within
the mfgrs ratings. A major reason to continue developement of external
anode tubes still goes on.
> Case #1: RCA, Altec, and Ampeg all tried using 6146B tubes
> in audio amplifiers.
We can't know all the exact reasons why they made the change, but cost
and availability were big issues. Aspin Pittman mentions the same
reasons in his Tube Amp Book. Many sources quote the above two reasons
as the primary reason, I agree with them.
> All of them later issued refits for 6550, too.
> The reason, mainly, was that the short stature of the 6146
> made too much heat dissipate through the base, which then
The typical base of a 6146 is a molded compound with a metal ring clamp.
I have versions which vary quite a bit. This tube was designed for many
uses and stays intact when properly operated within it's design ratings.
> became loose from the heat. Once an Ampeg player brought
> me the bulb from a 6146: the base glue had evaporated, and the
> solder had melted out of the pins. He tried to pull the tube
> out & the base stuck in the amp..bulb came out.
Aged base material and heat, bad news for any tube. The 6146 tube is
also made in B,C,W,F and R revisions that I know of. This tube should
opperate just fine in a properly designed circuit. I've experienced
glass bulb implosion, base compound detachment from the glass envelope
and pin fractures in 6L6 and many other tubes in the past. If you are
now able to provide adeqate air movement around a tube, it becomes less
difficult to exceed the mfgrs ratings.
Any airflow would have helped, base pin airflow would have helped much
more.
> Case#2: Take a look at an Eimac 3-500Z, for example.
> It has a BIG glass bulb, and the pins are long ways from
> the anode.
Have one right here, this tube often runs at more than 3000 volts on the
anode... The metal anode, grid and directly heated cathode pins are
large to conduct large amounts of heat and supply the voltage/current
required for normal operation.
> A big air system chimney covers it, too..the idea is to dissipate
> the heat off the glass before it gets to the pins and causes
> trouble.
Wrong, the mfgrs recomended operation of this tube is to pass air from
below the chassis ("air system socket"), past the base pins, alongside
the glass up past a large external anode plate cap that often was a
large piece of metal with heat radiation fins.
Tube element to base pin detachment from lack of cooling was a problem
for mfgrs for some time.
A well known amplifier (heath SB220) using two of these tubes has a
conservative fan blowing air across the base pins, glass and anode cap.
Because this amplifier was designed with cooling directed in an
efficient route past the base and anode pins, no chimney is required! At
power levels in excess of 1KW!
> I believe that applies to ceramic external-anode tubes as well, it's
> been awhile since I've peddled one, but I recall what happens when
> they overheat is that the ceramic seals crack. Thus the idea is to
> keep heat away from any ceramic/metal or glass metal seals,
It's all about air movement past the base pins/contacts and the anode
with the external anode becoming quite large. The ceramic type material
gives off only a small percentage of heat relative to the metal.
> not try to disspiate heat through them.
I try very hard to use the Metal parts of tubes to remove heat.
>
> As well as upside down tubes in Fenders are concerned,
> well, rock n' roll ain't rocket science. They're not 4CX35,000,
> and carrying a spare pair won't require hiring extra roadies...
>
No, but a small fan blowing air across the base pins would delay you
from installing those spares. Roadie or no roadie...
> >: >You might do this LV, I wouldn't. Have you ever measured the
> >: distortion
> >: >that occurs when you move the bias to a non linear portion of the
> >: >operating curve?
> >When they bring you an amplifier to fix, don't they ask you to make it
> >right? ... or do they ask you to make it "almost right". Didn't they
> >bring you the amplifier because it needed to sound better or be fixed to
> >sound better. I guess "almost" is good enough for your shop.
>
> Ned Sez:
>
> Skip, I think you missed the point here. A guitar amp isn't just
> an audio amp, it's an extension of a musical instrument,
I never questioned that part... just LV there
> and for distortion purposes they are treated as such.
> The question isn't avoiding distortion, unless the
> player wants a super clean sounding amp.
Do all guitar tube amp users start off wanting distortion?
A lot of players want the tube for it's natural sound, operated as clean
as practical. The distortion is added in various ways of choice by
design and operation. If a power amplifier is designed to operate clean
why not make it work as original and best as it can first. Then the
option of changing the sound can be done with mods, external equipment
and radical operation (turned way up).
Many people including myself are happy about doing said mentioned.
I just don't agree with calling tired/weak tubes biased wrong or at an
operating point where the tone more distorted, a practice I can support.
Many musicians in my area play tube amplifiers as clean as possible. Joe
Louis Walker was playing through here a while back. Quite a clean sweet
sounding amplifier he has.
> The idea is to add the harmonics that give the instrument
> the sound the player wants.
> Musical instruments aren't supposed to be linear,
> or without harmonics.
How about a nice tube amp with good tubes, operating where it should,
sounding like a million bucks...
You plug in your effects box or turn the knobs way up.
I plug in direct and play clean and clear.
We're both happy.
> If all we wanted was perfect
> sine waves, we'd all listen to tuning forks
> and audio oscillators.
no sine waves... Old Blues, Sade, Natalie Merchant (here her guitar
player? wow!), Gary Moore, Les Paul and Carl Perkins are in the CD
Cartridge now.
>
> >or you could take it to the guy who fixes it almost good enough...
> >Still haven't seen you mention anything about tube life vs heater > voltage,
I posted it last night, but the server was down. Look for some great
information in the next day or so.
> >a major player in any amplifier. I guess I might be doing that later.
>
> Don't bring that up, if them gurus get any ideas, they be selling
> filament voltage jackup mods to make the amp sound hotter..
>
It's been done, remember the TV tube fillament boosters? Add 3% more
voltage, get 20% more peak emission, 50% less life.
Hey! a new feature to add to an amplifier. You read it here first folks!
> >
> >: >> >An amplifier with the bias set wrong could have higher
> >: idle/operating
> >: >> >current and run hoter within it's ratings , but the amount of power
> >: >> the
> >: >> >tube can handle, remains the same. If the tubes are biased wrong
> >: but
> >: >> still
> >: >> >within their ratings, how will tube life be greatly reduced,
>
Who wrote this? I'd be interested in knowing how the tubes will run
cooler with higher static current.
> Actually, cooler tubes will last longer.
> There have been studies on that.
> But that's not the point, the point is to get the tone right,
> within acceptable parameters.
The tone should be right at the correct settings, call it
acceptable if you like.
> If some wants to run the tubes hot, and they think
> it sounds better, fine, they can carry a spare pair.
> It's their amp, their tone & their money.
Your right, if they choose to go that way, fine by me.
> Indy car tires would last a lot longer if would last a lot
> longer if they weren't pushed so hard,
> but the point of car racing is to win, not save tires...
Race car tires are considered used up after a certain lifespan, often
unpredictable. A guru tire changer installs the tire with a machine that
makes two groves in the rim which the factory doesn't require. The
installer and anyone who has the same machine setup can use the grooves.
The grooves alter the balence only slightly and would not be noticed at
slower speeds.
The tire changer in the pit crew next door has the proper equipment and
knowledge to quickly change the tire, leave off the groove mod and also
send his driver out on the track.
As the cars are neck and neck, driver 1 with the grooves steps on the
gas to gain speed. Driver 2 follows suit and passes #1 who has now
noticed a slight wobble and can't quite get enough control to pass #2 at
200mph.
Driver #2 wins
> Ned Carlson, Triode Electronics, Chicago, IL http://www.triodeel.com
> Open 12:30-8 PM CT, 12:30-5 PM CT Sat Closed Wed
> ph:773-871-7459 fax 773-871-7938 "where da tubes are"
> Email catalogs: email our CataBot: cat...@triodeel.com
Ned! I know who you are now... if your the same Triode Electronics I've
run into in the past.
Nice to meet up with you here.
Thanks for the civil post.
cheers
Skip May
nospa...@juno.com
Skip
> >
> > Ned Sez:
> > I think changing from Sylvanias to Sovteks, for example, or 12AT7's
> > wearing out, would cause a greater diff in open loop gain than a
> > a 1 ohm resistor would.
Sorry Ned, I missed one. The power amp sections of most tube and audio
amplifiers operate with feedback... ie closed loop.
skip
Kirk R. Patton
Sorry . . . really enjoyed the silliness of this diatribe but just
couldn't let the whole "capacitors in parallel with resistors" thing go
unresponded . . .
There are two main reasons why capacitors and resistors are used in
parallel in tube (and transistor) amp circuits. The first is to set up
different operating points for the A.C. and D.C. parameters of the tube,
this is different from "A.C. and D.C. gain"; most tube amplifiers do not
have D.C. servo circuits so D.C. gain characteristics are simply not
used. It is a relationship between A.C. gain and quescient D.C. current
, you know, like, uh, BIAS . . . Capacitors used in this manner are
usually large value (electrolytics) and are chosen for the longest
practical time constant -- i.e. the bypass electrolytic on the cathode
of the 12AX7 in the front-end of a Marantz 2 . . . or Mac . . . or God
knows how many others . . .
The other reason for the use of capacitors in parallel with resistors is
to create a phase lead, or phase lag, at a certain range of frequencies
for stability -- the frequencies we're talking about are well above the
audio range. This is either the same thing or related to (depending on
who you ask) as "time-domain performance." These networks are (supposed
to be) designed with an analysis of the gain-bandwidth product of each
stage of the amp, the phase characteristics of the components and
circuit (mainly transformers and coupling capacitors) and the intended
bandwidth of the final operating amp . . . I'm going to leave out the
discussion of feedback and "phase margin" for stability, that could take
hours. Anyway, the point is to "goose up" the circuit's behavior to
have good transient response and freedom from oscillation under all
loads and signals . . . and usually to have predictible behavior above
the audio sprectum (sic) -- usually you want the harmonics of an
instrument arrive at the same time as the fundamental, tuning the
behavior to that of a Bessel function is current thinking . . . .
But I digress. Oh I've worked on my share of Marshalls, Fenders,
Ampegs, Boogies, Hiwatts, Oranges, Voxes, Danelectros, Gibsons, Vegas,
Silvertones, Music Mans, etc.etc.etc. and generally enjoy them and the
people who play them . . . and I'm sure that many of the "stabilization"
networks used in these machines were designed with a box of parts, a
guitar, and a three-footer . . . . and that's perfectly valid . . . but
there are SOME technical reasons . . .
Skip
Gruvmyster wrote:
>
> Hi Skip,
Hi Doug!
>
> Where's your shop? I'd like to see it sometime. Call me jes.curious.
>
Would owning a shop better qualify me to post, Doug?
jes curious...
thanks
skip
Skip
Marko wrote:
>
> That's some pretty stupid commentary...I think the original poster's
> point was that no one has all the answers and that people should never
> take for gospel what they read on usenet...
>
> IMO that's some pretty sane advice....
>
> Not to mention LV has done some slamming himself on here and he is a
> big boy and can take some back without shedding too many tears...
>
> This brings up a very interesting point.
> From what I've seen, LV has TRULY helped many, many people, via this
> board. This is really wonderful, and I salute him for this.
>
I agree. It's great for people to offer up ideas and solutions. If
others don't agree a civil debate will bring all the points under the
light for the readers to read.
> There also seems to be a 'Heckle + Jive' personality that is unecessarily
> rude, crude, hurtful to others without knowing them, etc...whatever, that
> spews forth overshadowing the factual points he always tries to make.
>
Hopefully, less of this will happen in the future.
> So one person comes onto this board, and LV and he start into it.
>
> In an amazing display of Mob Mentality, several of the regulars, who hang
> out at the park with LV often, decide to simply attack the one person
> with insults.
I was expecting a drive by shooting also...
>
> However, for Everyone to technically answer this one person's questions
> directed at LV, is just Way too easy for LV!... Like LV is weak, feeble
> or something like that, and needs everyone to technically answer for him!
>
I'll drop the use of "Lapdog" until further notice...
> TIME to See Skippy and LV thumbwrestle one-on-one, so we can get to the
> meat of the matter.
>
I'm a vegan, but what the heck. Let's have some fun!
> Marko
>
>
Thanks Marko!
onward...
skip may
nosp...@juno.com
Teleologist
Ned Carlson <postm...@triodeel.com> wrote in article
<33ee3ff5....@news.chicago.il.ameritech.net>...
> Chicaguh hasn't had a mention yet..note there is quite a
> variety here...somebody will speak up for da Winny Ciddy yet,
OK how about Home Run Inn on the west side of Chicago for the best 'Vintage'
Pizza :-)
Ned Carlson
"Teleologist" <Teleo...@Sorry.NoEmail> wrote:
>OK how about Home Run Inn on the west side of Chicago for the best 'Vintage'
>Pizza :-)
According to my Big Blue Book, HR Inn is 4254 W 31st.
Not quite my interpretation of "west side".
Southwest side, more like it.
Taylor Street is "Near West Side" , at least the part where the
Italian restaurants are.
C'mon, where all the Vietnamese food fans?
Big squid tentacles! Chewy chewy...
Howzabout Korean (no dog jokes please)
OK, the appetizers look like Hollywood horror f/x.
But grillin' yer own steak at the table is fun..
Guatemalan! Tamales as big as yer head!
Phooey, I'm goin' home for enchiladas & a cold
margarita...
Teleologist
> "Teleologist" <Teleo...@Sorry.NoEmail> wrote:
>
> >OK how about Home Run Inn on the west side of Chicago for the best
'Vintage'
> >Pizza :-)
>
> According to my Big Blue Book, HR Inn is 4254 W 31st.
> Not quite my interpretation of "west side".
>
Hawthorne works, who knows what may have been invented on Home Run Inn
napkins<G>.
Robert Fries
Skip <nosp...@juno.com> wrote:
>I'm a vegan, but what the heck. Let's have some fun!
>
Does that mean you're from another planet? That would explain
EVERYTHING!
RF
Will Richardson
Ned Carlson
Skip <nosp...@juno.com> wrote:
>> >
>> > Ned Sez:
>> > I think changing from Sylvanias to Sovteks, for example, or 12AT7's
>> > wearing out, would cause a greater diff in open loop gain than a
>> > a 1 ohm resistor would.
>
>Sorry Ned, I missed one. The power amp sections of most tube and audio
>amplifiers operate with feedback... ie closed loop.
Exactly my point, Skip, the 1 ohm resistor's in that
feedback loop, too.
Your quote:
>It's a mod which changes the stage gain LV!
IOW, also the open loop gain before feedback is applied,
as well.
Duncan Munro gave a figure of like .08db, (80 millibels)
for the difference in stage gain with the 1 ohm resistor. In
comparison to the production tolerances of the other
parts in the circuit, that would be insignificant.
Thomas C. Clancy
In article <33ee3ff5....@news.chicago.il.ameritech.net>,
Ned Carlson <postm...@triodeel.com> wrote:
>Me, I'm an enchilada (or fill in your favorite Mexican food here)
>man,(Thai is swell, too) my wife doesn't even know how to make pizza.
>(OTOH, ever had chiles rellenos made with *red* chiles? Yum!
>BTW, those all-you-can-eat Indian buffets on Devon Ave gotta be
>dang near the best deal in town..)
>
>So I dropped out of the discussion.
>
>
>From what I can gather, New Haven CT, supposedly has the best
>pizza in the country. Brooklyn, Champaign, IL (Papa Del's),
>and Davis, CA (can't remember where) are right up there.
>variety here...somebody will speak up for da Winny Ciddy yet,
>Note "Chicago Deep Dish Pizza" was invented by a Texan.
>Says so right on the wall of Pizzeria Uno.
yeah, by a guy who wanted to open a tex-mex joint (since you
couldn't get tex mex in chicago then) . so he sort of merged
the two food types, a cross between a taco and a pizza.
Jeremy Epstein
In article <5sd957$87j$1...@netnews.upenn.edu>,
James Andrews <jandr...@sas.upenn.edu> wrote:
> On a similar semi-pizza-related note, this place in Fairless Hills PA
> makes a thing called... something, I forget. It's basically a deep-fried
> calzone. You get this puffed up fried dough, and when you open it at the
> bottom is a steaming pool of melted cheese and sauce and toppings....
> It's really to die for. Well, literally--as if eating that much cheese
> wasn't bad enough for you, they deep fry it. Geez....
>
> Jas.
If I remember right, they have some kind of strange name like a "hippie
roll" or suchlike. -j
-------------------==== Posted via Deja News ====-----------------------
http://www.dejanews.com/ Search, Read, Post to Usenet
Sander deWaal
On Mon, 11 Aug 1997 15:33:58 GMT, postm...@triodeel.com (Ned
Carlson) wrote:
>Skip <nosp...@juno.com> wrote:
>
>>Sorry Ned, I missed one. The power amp sections of most tube and audio
>>amplifiers operate with feedback... ie closed loop.
>
>Exactly my point, Skip, the 1 ohm resistor's in that
>feedback loop, too.
>
>Your quote:
>
>>It's a mod which changes the stage gain LV!
Ned,
Is this cerrem in disguise, or just the oberklangmeister?
Sander deWaal
Pegasus Audio
pegasu...@pi.net
All rights reversed
Jeff Vineburg
>Lord Valve Drooleth:
>Dammit, you guys are KILLIN' me! There AIN'T no pizza in Denver.
>There's stuff they CALL pizza, but it's like ketchup on a cracker.
Why didn't it occur to me to just ASK THE FAT GUY about pizza?
Oh yeah? Well you don't KNOW SHIT about pizza. Furthermore, the
transconductance of part-skim mozzarella rules it out for good tone.
It also makes you fart less.
Etc, etc.
--------------------------------------------------------------
Jeff Vineburg !je...@op.net! Nuclear Fish !je...@nuclearfish.com!
http://www.op.net/~jeffv http://www.nuclearfish.com
lefty guitar info, musical humor song parodies, as heard on Stern show
Joe Cocker Spaniel's page
Victor Rey
Frank Pepe's pizza in New Haven Connecticut is the Tweed Deluxe of pizza.
I think Pepe's is credited with being the first pizzeria in the U.S.
Vittorio Reyes
Ned Carlson
pegasu...@pi.net (Sander deWaal) wrote:
>Ned,
>Is this cerrem in disguise, or just the oberklangmeister?
Really, he's a student at University of Califonia-Davis.
No relation..I hope...
Ned Carlson
"Kirk R. Patton" <kirkp...@sprintmail.com> wrote:
>Sorry . . . really enjoyed the silliness of this diatribe but just
>couldn't let the whole "capacitors in parallel with resistors" thing go
>unresponded . . .
Did I mention that? Or are you responding to different post?
I don't see anything about caps in mine!
>But I digress. Oh I've worked on my share of Marshalls, Fenders,
>Ampegs, Boogies, Hiwatts, Oranges, Voxes, Danelectros, Gibsons, Vegas,
>Silvertones, Music Mans, etc.etc.etc. and generally enjoy them and the
>people who play them . . . and I'm sure that many of the "stabilization"
>networks used in these machines were designed with a box of parts, a
>guitar, and a three-footer . . . . and that's perfectly valid . . . but
>there are SOME technical reasons . . .
I don't mean to diss guitar amps, Kirk, only meant to point out that
the design objectives are different than for hifi amps.
What's important to one, might not be important to the other.
Note that as far as how well they hold up in service,
most guitar amps do purty darn good .
I'm sure there's plenty of players out there gigging
almost every day with 30 and 40 year old gear!
I wonder how a Jadis would survive a road tour..
Ned Carlson
"Teleologist" <Teleo...@Sorry.NoEmail> wrote:
>OK OK<g>, However, it's just a stone's throw from the old Western Electric
>Hawthorne works, who knows what may have been invented on Home Run Inn
>napkins<G>.
BTW, did you know there used to be a machine at Hawthorne that
ran 24 hrs a day smashing old telephones to smithereens?
David Letterman would've loved it...
Jeremy Epstein
In article <5sh134$9...@sjx-ixn5.ix.netcom.com>,
detr...@ix.netcom.com(Lord Valve) wrote:
> Lord Valve Drooleth:
> Dammit, you guys are KILLIN' me! There AIN'T no pizza in Denver.
The altitude probably kills the yeast in the dough - like your brain
cells, M'lord.
> ...my favorite
> was from a little joint called Pop's Italian Vineyard Room, in Wheaton,
> MD., just outside of DC. (Same town that Chuck Levin's Washington
> Music Center is located in. I useta work for Chuck when I was in high
> school...but that's another story...) Senators and Congressmen
> frequented the place, and many pizzas were spirited away by uniformed
> limousine drivers at all hours of the night. (No delivery...if you
> wanted one from Pop's, you hadda go get it.)
I'll make a note of it - next time I DC it you know I'll be checking the
competition!
Supposedly Sinatra sends flunkys by limo to Patsy's here in Brooklyn to
pick up a couple dozen pies - there are photos of Patsy with The Chairman
Of The Board up on the wall. Myself, I time my road trips into New
England so we hit New Haven around lunchtime (my wife shares my
enthusiasm for the New Haven product so it's an easy sell.) I've split
whole pies with her right on the hood of our car while our daughter
sleeps, unaware of what she's missing.
> <snip> We DO have some
> killer Tex-Mex here, though. If you're ever through Denver, try the
> Blue Bonnet Cafe, or the Chipotl Mexican Grill. <burp> <and worse>
> This is lookin' like alt.lets.eat, huh? roflmao!
>
> Lord Valve
> oh...@lunchtime.com
My turn to drool - none of the tex-mex places I know in New York are
worth a burlap rice sack. Anybody have any advice? It gets so it's almost
worth visiting my in-laws in California . . . .
-j, signing off from alt.food.nyc
Kirk R. Patton
Ned, I wasn't responding to your posting, it was the, uh, poster of the
previous drivel . . .
I completely agree with your point about, well, recognizing the
differences between design approaches as they relate to different
appplications -- as a matter of fact I feel that this is what is usually
left out of the "technical" discussions on this newsgroup . . . I was
sort of taken aback with the bogus statement regarding stabilization
networks by someone else . . .
This is a bit of a sore point for me I guess . . . most of my work on my
own designs these days is based on optimizing the relationships between
time-domain (phase) performance and super-and-sub-sonic Bode plot data .
. . would very much be interested in some real insight from others
experienced with optimizing feedback and stability . . .
I am not a "foo-foo" high-end guy or "guitar guy", most of my affection
for various kinds of equipment comes from:
A) What I have personally enjoyed listening to or working on
B) What I have made a decent profit working on . . .
Guitar amps and vintage hi-fi fit both criteria . . .
David N. Barnett
Jeremy Epstein <7066...@compuserve.com> wrote:
>In article <33e86caa...@news.chicago.il.ameritech.net>,
> postm...@triodeel.com wrote:
>
>> If you've been to either place and done ate pizza,
>> I'll *possibly* respect your opinion.
>>
>> Ned Carlson, Triode Electronics, Chicago, IL
My news service is spotty at best, so I messed the original message,
but if Ned's comment was directed at me, then damn straight I've been
to both places and eaten the pizza. There's lotsa good food in
Chicago, but their indigenous pizza ain't fit to eat. Deep dish my
ass. Feh!
On the other hand, Chicago is a MUCH better source for NOS tubes....
--dnb, who does occasionally escape from the state of Arkansas
Bluemuse
>>>Frank Pepe's pizza in New Haven Connecticut is the Tweed Deluxe of
pizza.
I think Pepe's is credited with being the first pizzeria in the U.S.
<<<
I've heard this, too, and it's worth the hour wait in line. They started
in 1925 (they were originally in the building in the back where The Spot
now is). My great-grandmother was selling apizza in New Haven before Pepe,
but she didn't have a pizzeria (or, I suspect, the coal-fired brick
ovens).
--Bob Farace
"I only believe in fire." --Anais Nin
JER
Late Night Pizza in Athens OH makes a killer artichoke and parmesan pizza.
Can't speak for any of their other pizzas though. Rich and decatant. mmmmm
Jack
remove _no_spam_ to reply
Gruvmyster
Well, some experience *would* help...but I must admit even if you were
Eric Johnson's personal tech you'd still probably be an idiot.
TimTube
In article <33F0CB...@mail.idt.net>, Gruvmyster
<dhau...@mail.idt.net> writes:
>
>Well, some experience *would* help...but I must admit even if you were
>Eric Johnson's personal tech you'd still probably be an idiot.
>
>Doug
Sorry, qualfication for that job would require at least a minimal
knowledge of guitar amps.
Tim
A great amp can make a lousy guitar sound great.
A lousy amp will make a great guitar sound lousy.
Jeff Vineburg
>>From what I can gather, New Haven CT, supposedly has the best
>>pizza in the country. Brooklyn, Champaign, IL (Papa Del's),
>>and Davis, CA (can't remember where)
Woodstock's.
Jeff Vineburg
>Next time you're in Philadelphia, give me a call, we'll go to Marra's on
>Passyunk Ave. in S. Phila.
With gen-you-wine Eyetralyens behind da countah.
And while you're eating, someone will steal the radio out of your car,
which has been triple-parked, as it's the law in So'filly.
>Of course, everyone has different ideas--I personally could never believe
>that Chicago-deep-dish-style pizza could ever be as good as what I
>consider a "normal" one.
It's not belief, James, it's fact :)
Michael Cullen
You guys are a pain in the butt, with all this food talk! 1am, and I'm hungry
as! :-)
The Pizza shop around the corner, (down here in Perth, Western Australia), makes
*great* pizza. Really good stuff. Their best one is Chicken Satay. Man, I just
love that one.... Of course, I don't eat there often - GAS & AAS rules.....
cheers,
Mic. (http://netserv.net.au/tiger/)
Cross Purposes Studios (Web & Graphic Design)
War doesn't determine who's right, just who's left.
Ned Carlson
davidb...@aristotle.net (David N. Barnett) wrote:
>My news service is spotty at best, so I messed the original message,
>but if Ned's comment was directed at me,
No, it wasn't...
>then damn straight I've been
>to both places and eaten the pizza. There's lotsa good food in
>Chicago, but their indigenous pizza ain't fit to eat. Deep dish my
>ass. Feh!
Too much cheese for me.
>
>On the other hand, Chicago is a MUCH better source for NOS tubes....
It sure worked for me!
Dale VanZile
Jeff Vineburg wrote:
>
> >>From what I can gather, New Haven CT, supposedly has the best
> >>pizza in the country. Brooklyn, Champaign, IL (Papa Del's),
> >>and Davis, CA (can't remember where)
>
> Woodstock's.
Buono's in Mesa, AZ.
Dutch
--
<Dale.V...@asu.edu>
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