OT: tube amp questions
Bassy
alt.guitar.amps.
Finally got a new tube head, and I have some questions:
- I understand the PT and OT functions: what does the choke do? Why
wasn'it there in my former JCM900 head?
- When the amp is powered up but in standby there must be a speaker
connected in order to avoid blowing the OT or is only when the head is
actually working?
- The amp's a 100 watt head with 4 EL84's. If I take out the outer
ones to make it 50w how must I adjust the impedance?
Thanks!
David Axt
"Bassy" <do...@spam.me> wrote in message
news:42c20c06...@news.libero.it...
Alt.guitar.amps is just too political anyway right now. You are not missing
a thing.
A choke help smooth the ripple in a power supply. Better amps have chokes.
Some amp designs do not. I don't know about the Marshall amps.
A tube amp likes to see a "load" when operating. You can put an amp on
standby while changing speaker cabinets for example.
I believe that you must double the speaker impedance if you remove 2 of 4
output tubes. For example if your cabinet was 8 ohms with 4 output tubes
then you should use a 16 ohm cabinet with only 2 output tubes.
-David
Ether
David Axt wrote:
> "Bassy" <do...@spam.me> wrote in message
> news:42c20c06...@news.libero.it...
> > Sorry for the misplaced post, but lame Italian provider isn't carrying
> > alt.guitar.amps.
> >
> > Finally got a new tube head, and I have some questions:
> >
> > - I understand the PT and OT functions: what does the choke do? Why
> > wasn'it there in my former JCM900 head?
> >
> > - When the amp is powered up but in standby there must be a speaker
> > connected in order to avoid blowing the OT or is only when the head is
> > actually working?
> >
> > - The amp's a 100 watt head with 4 EL84's. If I take out the outer
> > ones to make it 50w how must I adjust the impedance?
> >
> >
> > Thanks!
>
> Alt.guitar.amps is just too political anyway right now. You are not missing
> a thing.
Except for all the fun! Sure, there's a lot of of nonsense being slung
around AGA, but you can still get your amp questions answered. And if
your ISP doesn't carry it, just read & post on Google Groups. You can
get that anywhere.
>
> A choke help smooth the ripple in a power supply.
Yep. Tightens up the power supply in general.
> Better amps have chokes.
Depends on what you mean by better!
> Some amp designs do not. I don't know about the Marshall amps.
>
> A tube amp likes to see a "load" when operating. You can put an amp on
> standby while changing speaker cabinets for example.
If you don't have a load present while the amp is operating, the OT
sees an infinite secondary impedance--not good. (Fender amps have a
shorting jack for this reason. A short in the OT secondary is better
than totally open.)
>
> I believe that you must double the speaker impedance if you remove 2 of 4
> output tubes. For example if your cabinet was 8 ohms with 4 output tubes
> then you should use a 16 ohm cabinet with only 2 output tubes.
Right.
Regards,
--E
Bassy
wrote:
>A tube amp likes to see a "load" when operating. You can put an amp on
>standby while changing speaker cabinets for example.
You mean that the amp needs to see the load only when actually
operating? The way you worded it seems to imply that if you have the
amp on standby with no cab connected you won't damage it. Have I got
it right?
nm...@wt.net
wasn'it there in my former JCM900 head?
Well, it basically provides for better voltage regulation.
Also, you can get by with a smaller value of filter cap.
The voltage will be less likely to soar under no load,
and better regulation under load. This increases
the dynamic range of the amp. Less likely to fart out under
heavy hits...But....Some prefer a lot of sag for tone.
Tone wise, to many, newer amps power supplies are *too* well
regulated, unless it's for bass, or a high headroom jazz box..
- When the amp is powered up but in standby there must be a speaker
connected in order to avoid blowing the OT or is only when the head is
actually working?
It should be ok in standby as the high voltage is off the plates..
But....I always make sure the speakers are hooked up before
even powering up the amp. Like fastening seat belts in a car..
You don't want to get in any bad habits...One mistake of forgetting
to hook them up, and you could be in deep doo-doo.
- The amp's a 100 watt head with 4 EL84's. If I take out the outer
ones to make it 50w how must I adjust the impedance?
You can't really, I don't think...Thats a function of the tubes vs OT
design...
The impedance should be *off* if you remove two tubes...
I'm not a real fan of doing that, but many do I guess...I think there
are better methods to use...IE: powerbrakes, etc...That way the
amps stays happy, and you'll get better tone , driving it harder...
The only thing you would miss from full crank, would be speaker
breakup...Usually, the mismatch from dumping two tubes will
make the amp kinda "flat" sounding.. I'd get a few opinions on
that with the marshall bunch, before I tried it...I'm not up on that
model amp...
MK
Jim Anable
> Sorry for the misplaced post, but lame Italian provider isn't carrying
> alt.guitar.amps.
>
> Finally got a new tube head, and I have some questions:
>
> - I understand the PT and OT functions: what does the choke do?
It filters ripple out of the DC power supply.
Why
> wasn'it there in my former JCM900 head?
Don't know. Many Marshalls, including my JMP 2204, use chokes.
>
> - When the amp is powered up but in standby there must be a speaker
> connected in order to avoid blowing the OT or is only when the head is
> actually working?
In the vast majority of amp designs, the standby switch removes the
voltage from the output transformer, so it's entirely safe to fiddle
with speaker cables on standby. Even in designs that don't do this,
you're not likely to have a problem with no signal going through the amp.
>
> - The amp's a 100 watt head with 4 EL84's.
Do you mean EL34? There ain't no 4xEL84 amp out there that can do 100W.
If I take out the outer
> ones to make it 50w how must I adjust the impedance?
Double what it would've been with four tubes.
Jim Anable
Yes, but don't forget, switch off standby, and start strumming and
increasing the volume. You're likely to get flyback peaks that will
punch through OPT insulation and/or arc over the tube sockets.
Jim Anable
One comment. You can't pull two tubes from a Marshall and expect it to
sound like a 50W Marshall. You've got more OPT iron, and more voltage
on the plates.
Guncho
WARNING!
This is totally wrong! You cut the impedance in half. NOT DOUBLE IT.
Ie If you were running out of the 8ohm plug with four tubes now you
would run out of the 4ohm jack.
Chris
Guncho
> You can't really, I don't think...Thats a function of the tubes vs OT
> design...
> The impedance should be *off* if you remove two tubes...
> I'm not a real fan of doing that, but many do I guess...I think there
> are better methods to use...IE: powerbrakes, etc...That way the
> amps stays happy, and you'll get better tone , driving it harder...
> The only thing you would miss from full crank, would be speaker
> breakup...Usually, the mismatch from dumping two tubes will
> make the amp kinda "flat" sounding.. I'd get a few opinions on
> that with the marshall bunch, before I tried it...I'm not up on that
> model amp...
> MK
That is totally wrong. If you pull out the two outside tubes you now
have a 50 watt amp and you cut the impedance in half. Other than that
there is no other difference. Now you can crank the amp and it won't
be so loud.
CHris
Guncho
> Double what it would've been with four tubes.
WRONG!
You cut it in half. NOT DOUBLE IT.
CHris
Guncho
Well I do this with my Seymour Duncan Convertible and I don't notice
any sound difference. It's just not as loud.
Have you ever done this with a Marshall Jim?
CHris
The Filthy Sanchez
"David Axt" <daxtATpacifierDOTcom> wrote in message
news:11c44m0...@corp.supernews.com...
>
> "Bassy" <do...@spam.me> wrote in message
> news:42c20c06...@news.libero.it...
> > Sorry for the misplaced post, but lame Italian provider isn't carrying
> > alt.guitar.amps.
> >
> > Finally got a new tube head, and I have some questions:
> >
> > - I understand the PT and OT functions: what does the choke do? Why
> > wasn'it there in my former JCM900 head?
> >
> > - When the amp is powered up but in standby there must be a speaker
> > connected in order to avoid blowing the OT or is only when the head is
> > actually working?
> >
> > - The amp's a 100 watt head with 4 EL84's. If I take out the outer
> > ones to make it 50w how must I adjust the impedance?
> >
> >
> > Thanks!
>
> Alt.guitar.amps is just too political anyway right now. You are not
missing
> a thing.
>
> A choke help smooth the ripple in a power supply. Better amps have
chokes.
> Some amp designs do not. I don't know about the Marshall amps.
Some amps use a big resistor instead, but generally a choke is better
>
> A tube amp likes to see a "load" when operating. You can put an amp on
> standby while changing speaker cabinets for example.
If there is a good reason for operating in standby without a load, i.e
changing cabs, troubleshooting, great. Otherwise, for most folks the best
idea is always have it connected to a proper load whenrever the amp is
plugged in.
>
> I believe that you must double the speaker impedance if you remove 2 of 4
> output tubes. For example if your cabinet was 8 ohms with 4 output tubes
> then you should use a 16 ohm cabinet with only 2 output tubes.
Sort of sometimes. All amps can't just have a pair of tubes removed, so you
need to find out more about your amp. Also, no way no how is a quad of
EL-84's putting out 100 watts. A few amps running them way hotmay get 50,
but 30-35 is more typical for a quad of EL-84s in most amp designs.
>
> -David
>
>
Guncho
> Sort of sometimes. All amps can't just have a pair of tubes removed, so you
> need to find out more about your amp. Also, no way no how is a quad of
> EL-84's putting out 100 watts. A few amps running them way hotmay get 50,
> but 30-35 is more typical for a quad of EL-84s in most amp designs.
Any amp with a "push pull" design with four power tubes you can.
Chris
The Filthy Sanchez
"Guncho" <cgu...@hotmail.com> wrote in message
news:1120062018.1...@g14g2000cwa.googlegroups.com...
Generally yes, although the results (even with the proper loading on the OT)
may not always be optimal. Some amps are specifically designed to allow
this. Also, I've seen amps where the physical layout of the tubes doesn't
lend itself to the old "remove the two outside tubes" idea, i.e., they don't
have the four output tubes lined up in one row, but instead have a 2x2
arrangement. I hesitate to give blanket advice to people who don't know
jack about electronics to just pull the two "outside" tubes on any four
power tube amp.
Ether
Guncho wrote:
> > You can't really, I don't think...Thats a function of the tubes vs OT
> > design...
> > The impedance should be *off* if you remove two tubes...
> > I'm not a real fan of doing that, but many do I guess...I think there
> > are better methods to use...IE: powerbrakes, etc...That way the
> > amps stays happy, and you'll get better tone , driving it harder...
> > The only thing you would miss from full crank, would be speaker
> > breakup...Usually, the mismatch from dumping two tubes will
> > make the amp kinda "flat" sounding.. I'd get a few opinions on
> > that with the marshall bunch, before I tried it...I'm not up on that
> > model amp...
> > MK
>
> That is totally wrong. If you pull out the two outside tubes you now
> have a 50 watt amp and you cut the impedance in half.
No. If you pull two of the four tubes, the impedance will DOUBLE. You
will need to have TWICE the ohm load on the secondary side. (So if you
had an 8-ohm speaker with four tubes, you will need a 16-ohm speaker
with two tubes.)
> Other than that there is no other difference. Now you can crank the
> amp and it won't be so loud.
>
> CHris
True, it will not be as loud. Just make sure you match the impedance
correctly.
--E
Ether
Chris, you're mistaken. Parallel impedances are AVERAGED. So two tubes
in parallel have half the impedance of one tube.
So if you pull one of two tubes (or two of four), you DOUBLE the
impedance.
--E
Jim Anable
I'm not gonna be the guy to tell all owners of four tube amps that it's
always safe to pull two tubes. Bias will change, for one thing. On
some amps, you can't adjust the bias.
Ether
Sorry--not "averaged"; that should be basically "halved." You figure
out parallel resistances by adding the reciprocal of each value, and
then taking the reciprocal of that total. See here:
http://mathforum.org/library/drmath/view/51490.html
http://www.computertorture.com/noncompliant/parallel/simple.html
Regards,
--E
Jim Anable
My answer was confusing. If you pull two tubes from a four tube amp,
the impedance selectors on the back of the amp are now DOUBLE what they
say. THAT'S what I was trying to say.
My reasoning is as follows:
When you reduce from two to one plate on each side of the OPT, you have
DOUBLE the impedance. Therefore you need to DOUBLE the readings on the
impedance selector switch. Using a 16 ohm cab? Plug into 8 ohms with
half the normal output tubes.
Internet descriptions on how to do this are often confusing at best.
Don't take my word for it, ask a tech.
Jim Anable
>
> Guncho wrote:
>
>>>You can't really, I don't think...Thats a function of the tubes vs OT
>>>design...
>>>The impedance should be *off* if you remove two tubes...
>>>I'm not a real fan of doing that, but many do I guess...I think there
>>>are better methods to use...IE: powerbrakes, etc...That way the
>>>amps stays happy, and you'll get better tone , driving it harder...
>>>The only thing you would miss from full crank, would be speaker
>>>breakup...Usually, the mismatch from dumping two tubes will
>>>make the amp kinda "flat" sounding.. I'd get a few opinions on
>>>that with the marshall bunch, before I tried it...I'm not up on that
>>>model amp...
>>>MK
>>
>>That is totally wrong. If you pull out the two outside tubes you now
>>have a 50 watt amp and you cut the impedance in half.
>
>
> No. If you pull two of the four tubes, the impedance will DOUBLE. You
> will need to have TWICE the ohm load on the secondary side. (So if you
> had an 8-ohm speaker with four tubes, you will need a 16-ohm speaker
> with two tubes.)
There seems to be CONFLICTING information on this subject on the internet.
I'm not sure who is right.
Guncho
Maybe we're getting confused.
With four power tubes you are running out of an 8ohm jack into an 8ohm
cab.
With two power tubes you would run out of the 4ohm jack into an 8ohm
cab.
You can't change the impedance of the cab.
Chris
Jim Anable
I have no need to pull two tubes from a Marshall because I bought the
50W JMP 2204 off the showroom floor over 20 years ago. ...because it
sounded better than the 100W. Why did it sound better? One reason is
that it has LESS VOLTAGE on the output plates, so it distorts earlier.
Pull two tube off a 100W Marshall that has more voltage to begin with,
and you have even MORE voltage! More voltage equals more headroom. NOT
a good thing when you want Marshall distortion.
You should also rebias if you pull two tubes.
nm...@wt.net
No, I don't think so. But opinions will vary... I'm fairly
ignorant about geetar amps in general, but I have been
playing with tubes since I was in jr hi. I'm not a total dummy
in that regard.
I still think a powersoak is the *premium* method to use
in this case. But opinions will vary...
If you pull out the two outside tubes you now
have a 50 watt amp and you cut the impedance in half.
In my first reply, I didn't take into account changing speakers...
When he asked about "changing" the impedance, I assumed
he meant between the tube and OPT, and outwards.
I wasn't sure how the speaker impedence rule worked out in
that case...But many seem to claim backwards from you...
I assumed he was going to run it into the same speaker.
Other than that
there is no other difference. Now you can crank the amp and it won't
be so loud.
Oh, there are differences, trust me... I'm not saying you can't do it.
Many do...I'd just be careful... Actually, If I wanted a 50w amp,
I would have bought a 50w amp in the first place...100w is too much
power for 89.5 percent of the people that "play out"... Or at least
if you want a decent breakup tone without killing peoples ears...
Thats why I was scared to get a twin reverb.
Too much dang headroom... I'm really glad I got the 45 watt
super reverb instead. To me, for average bar, etc use, it's
nearly perfect. If it ain't loud nuff, I'll mike it to a PA...
Only the big area gigs need big power, and they oughta be using a
PA anyway. When I get a Marshall for my dirty channel, it's almost
certainly going to be a 50 watter, not 100.
Heck, the place I've been going to lately, I wouldn't be able to fully
crank 50w, without the bartender going ballistic. It's a pretty small
place...
If I needed both a 100w amp, and a 50w amp, I'd get one of each.
But, thats just me... I can't see myself ever needing 100w, unless
maybe
I started doing stadium gigs. And that will probably be at o-clock...
Even then, it wouldn't be really needed, being it's all PA'd. I could
use a
champ. I always prefer to use the least power I can, as long as I can
keep up. Get better tone that way...I don't play jazz. :/
Some jazz guys probably need the big power, if they play real clean.
But that ain't me. MK
Jim Anable
>>A tube amp likes to see a "load" when operating. You can put an amp on
>>standby while changing speaker cabinets for example.
>>
>
>
> You can also turn damn thing off, right? I mean if you're going to start to
> fiddle, doesn't it make sense to just turn it off?
Turning a tube amp off and on puts some additional stress on it. Better
to go to standby, if it's an option.
Ginger
Is there a small pot somewhere inside the amp to adjust? How would you
know when it was correct (are there test leads where you should see a
certain voltage)?
Ether
Guncho wrote:
> Ether wrote:
> > Guncho wrote:
> > > > Double what it would've been with four tubes.
> > >
> > >
> > > WRONG!
> > >
> > > You cut it in half. NOT DOUBLE IT.
> > >
> > > CHris
> >
> > Chris, you're mistaken. Parallel impedances are AVERAGED. So two tubes
> > in parallel have half the impedance of one tube.
> >
> > So if you pull one of two tubes (or two of four), you DOUBLE the
> > impedance.
> >
> > --E
>
> Maybe we're getting confused.
>
> With four power tubes you are running out of an 8ohm jack into an 8ohm
> cab.
Right...
>
> With two power tubes you would run out of the 4ohm jack into an 8ohm
> cab.
Right--you have just effectively doubled the impedance. (The 8-ohm load
is twice what you would usually attach to the 4-ohm output if all four
output tubes were present.)
>
> You can't change the impedance of the cab.
Sure you can. Just rewire as series/parallel, or disconnect two of the
speakers (if all are wired in parallel).
--E
Jim Anable
You can do google searches. I'm hesitant to explain, because it usually
involves being around a live circuit with voltages that BEST CASE will
hurt like hell, and worst case, KILL YOU DEAD.
I use a bias probe tool, which makes the job easier (especially when I
own multiple amps).
Pay attention to the safety warnings! If you don't understand the
basics of electricity, it's cheaper to hire a tech than pay for a funeral.
Guncho
Man I feel sorry for anyone trying to get a straight answer out of this
thread.
Once again.
If you pull out two power tubes, you cut the impedance in half.
ie If you were running out of the 8ohm jack now you would run out of
the 4ohm jack.
CHris
Jim Anable
Or, like I said, you DOUBLE the number on the back of your amp on the
impedance selector. See how that is MUCH LESS CONFUSING than saying
"you cut the impedance in half"????
Guncho
Jim
That is wrong.
You cut the number in half. Not double it.
If you were running out of the 8 ohm jack with four tubes you DON'T run
out of the 16ohm jack with two.
Chris
nm...@wt.net
You cut the number in half. Not double it.
If you were running out of the 8 ohm jack with four tubes you DON'T run
out of the 16ohm jack with two.
I think thats right...I was looking into that a bit, and it seems
you have two choices. Double the total impedance value of the
speakers, or, half the impedance if you are changing an impedance
selector.
So if it was originally 8 ohms,and you just changed the tap on
the OPT, you would select 4 ohms.. Or...You could double the
impedance of the speakers to 16 ohms using the same 8 ohm
tap. Either would keep the same appx transformation ratio.
I *think* this is right.... :/ MK
Guncho
Yes that is right. And seeing how changing the ohm selector switch is
usually a lot easy and more cost effective than rewiring your speaker
cabinet or buying a new one most people just flick the switch.
Chris
Jim Anable
NO, it is correct. READ and attempt to comprehend before once again
just trying to disagree with me!
> You cut the number in half. Not double it.
You cut what in half? See how what you are saying can easily be
confused????
>
> If you were running out of the 8 ohm jack with four tubes you DON'T run
> out of the 16ohm jack with two.
Of course not. That is NOT what I said!
Read, READ, *READ* what I said:
"...you DOUBLE the number on the back of your amp on the impedance
selector."
It sucks to be wrong all the time, don't it? ;^)
>
> Chris
Jim Anable
nm...@wt.net wrote:
> That is wrong.
>
> You cut the number in half. Not double it.
>
> If you were running out of the 8 ohm jack with four tubes you DON'T run
> out of the 16ohm jack with two.
>
> I think thats right...I was looking into that a bit, and it seems
> you have two choices. Double the total impedance value of the
> speakers, or, half the impedance if you are changing an impedance
> selector.
> So if it was originally 8 ohms,and you just changed the tap on
> the OPT, you would select 4 ohms..
CORRECT, and THAT is what I said. You now have to DOUBLE what the
impedance selector says on the back of the amp! Double the 4 ohms
equals 8, right?
Guncho
Jim
For fucks sake you are wrong.
If you take out two power tubes you DIVIDE THE OHMS BY 2.
You can double the selction of your ohm switch all you want but don't
come crying to me when your amps blows a gasket.
Chris
nm...@wt.net
Well...I think it's actually a just failure to communicate...He's
thinking
right, it just seems wrong the way he is describing it. He's saying
if you dump two tubes, and use say the 4 ohm tap, your actually
impedance would be double, or 8 ohms. Or twice was the tap
says. You are both right. MK
David Axt
Let's assume that you are using 4 output tube amp into a 8 ohm speaker
cabinet. If you pull two output tubes you can either:
A) Use a 16 ohm speaker cabinet
or
B) Set the selector switch on your amp to 4 ohms (while still using your 8
ohm cabinet.)
Sorry for any of the confusion.
-DA
Jim Anable
>
>
> Jim
>
> For fucks sake you are wrong.
Guncho, I am *CORRECT*. The problem is that you have absolutely no
reading comprehension, at least when your goal is to contradict me!
>
> If you take out two power tubes you DIVIDE THE OHMS BY 2.
Please enroll in a remedial reading class.
You don't realize that you are saying the same thing that I wrote, only
in a more confusing way.
>
> You can double the selction of your ohm switch all you want but don't
> come crying to me when your amps blows a gasket.
>
> Chris
Guncho. Read this really, really slowly, as many times as it takes:
Multiplying the impedance selector value on the back or your amp, then
matching to your actual cab value IS THE SAME THING as dividing the cab
value by two!
NOW do you get it???
If not, there's no hope.
Jim Anable
> Allow me to clarify.
>
> Let's assume that you are using 4 output tube amp into a 8 ohm speaker
> cabinet. If you pull two output tubes you can either:
>
> A) Use a 16 ohm speaker cabinet
...leaving the amp set to 8...
But that's a bit confusing because most guys don't have a bunch of
different impedance cabs laying around.
>
> or
>
> B) Set the selector switch on your amp to 4 ohms (while still using your 8
> ohm cabinet.)
Exactly. There's more than one way to communicate this. Some of us get
it, some of us don't. I say multiply the value of the tap by two, and
match to your cab. Another guy says I'm wrong, because he can't
understand that multiplying the value on the amp by two and matching to
your cab IS THE SAME THING as using a tap that is one half the value of
your cab!
>
> Sorry for any of the confusion.
It's been a source of confusion for YEARS on the net. Not YOUR fault ;^)
>
> -DA
Jim Anable
Jim Anable
>> Guncho wrote: For fucks sake you are wrong.
Guncho's problem: no matter what I say, Guncho immediately tries to
disagree. This COMPULSION often results in Guncho being WAY off base in
his response. Or he completely miscomprehends what I posted, and
answers to something that I didn't even say...
It's very frustrating. I'm a VERY easy going guy. But I often have to
wonder if the guy is (A) very dense, with poor reading comprehension;
(B) purposely trying to push my buttons; or (C) all of the above.
The Filthy Sanchez
"Jim Anable" <j...@seattle-attorney.com> wrote in message
news:11c8tro...@corp.supernews.com...
Ether
Ay, yie, yie...
Chris--Imagine you have an amp with ONE speaker output, and your amp
requires an 8-ohm speaker. You have four power tubes.
When you pull two of the output tubes, the impedance will DOUBLE. You
will now need a 16-OHM speaker.
Clear?
Regards,
--E
Ether
Now, don't go promoting smoking, Jim.
--E
Ether
The Filthy Sanchez wrote:
Yeah--but what a fireworks show for the 4th! ;)
(Or should that be the "8th")?
--E
Ether
It's called "Wheatonitis". ;)
--E
Ether
"And an ORANGE DRINK!!!!!! AAaaaaaaaaaahhhhhhh!"
--E
Jim Anable
>
> Jim Anable wrote:
>
>>nm...@wt.net wrote:
>>
>>>That is wrong.
>>>
>>>You cut the number in half. Not double it.
>>>
>>>If you were running out of the 8 ohm jack with four tubes you DON'T run
>>>out of the 16ohm jack with two.
>>>
>>>I think thats right...I was looking into that a bit, and it seems
>>>you have two choices. Double the total impedance value of the
>>>speakers, or, half the impedance if you are changing an impedance
>>>selector.
>>>So if it was originally 8 ohms,and you just changed the tap on
>>>the OPT, you would select 4 ohms..
>>
>>CORRECT, and THAT is what I said. You now have to DOUBLE what the
>>impedance selector says on the back of the amp! Double the 4 ohms
>>equals 8, right?
>>
>>Or...You could double the
>>
>>>impedance of the speakers to 16 ohms using the same 8 ohm
>>>tap. Either would keep the same appx transformation ratio.
>>>I *think* this is right.... :/ MK
>>>
>
>
> Jim
>
> For fucks sake you are wrong.
Okay. You FINALLY figured out that I was CORRECT! No "sorry 'bout that"?
Guncho
Christ is that what you were tying to say?
Why didn't you just say that then?
Yes that would totally work to.
Guncho
You Love To Hate Him
Guncho
Jim
This is what you said:
"If I take out the outer
> ones to make it 50w how must I adjust the impedance?
Double what it would've been with four tubes. "
Call me dense but that looks like you telling him that if he was
running out of the 8 ohm jack he would now run out of the 16 ohm jack.
Which is totally wrong!
Chris
Guncho
Yes that is totally clear.
How many amps only have one speaker output that aren't combos?
Chris
Guncho
Oh that's easy. Just make your amp watch a lot of the Daily Show and
he will be biased to the left.
Hee hee.
Actually I didn't touch the bias on my amp (Seymour Duncan Convertible)
when I pulled out two tubes and it sounds great!
Chris
Jim Anable
In plain black and white, SEVERAL times!
>
> Why didn't you just say that then?
Why didn't you just READ it?
Ether
Ever hear of the Fender Bassman, Bandmaster, Bandmaster Reverb,
Showman, and Dual Showman Reverb? All of these heads have a single tap
on the OT. (As do about a billion Fender combo amps.)
Loads of other amps also have one OT tap. It's pretty darn common.
Try to get out more!
--E