I would like to see pictures of Andres projects.
edo
rec.audio.tubes
"Henry A. Pasternack" <hpast...@rcn.dot.com> wrote in message
news:3fe7be9d$0$4748$61fe...@news.rcn.com...
> Ive been hearing about them for years and am extremely curious to see
> what they look like. I imagine with Andres experience and resources
> his amplifiers and speakers must be extremely impressive.
>
> What say, Andre?
Jezus you are a fuckwit Pasternack.
Do you also think an X-Ray of Einsteins brain would look impressive
too ???
Everyone knows his face was a disaster area.
Any X-Ray of you brain would be blank.
.......... Phil
You have to understand Plodnicks outlook, Phil. He has no original ideas of his own. When he actually built an amp, one, it was a copy of a bog-standard design. After I told him I didnt want to see the photographs of his twee little amp, Pasternack still sent them to my mailbox. I trashed them unopened. But from others I understood he poured all his frustrated creativity into the exterior of the amp. The interesting thing is that he thought the appearance of the amp was the most important thing about it, not the sound. He didnt even publish the schematic until years later, and then it was dullsville. Pasternack and a whole lot of other guys who hang out on RAT think that workmanship can be substituted for originality. Turner even tells us he likes slo-o-o-o-o-w-w people. Well, they dont come much slower than the Tacky Turner Trolls.
I dont imagine Pasternack will understand why you are instinctively right about my protos. My interest is in how the electronics work. I dont waste time and effort making beautiful fittings for an item I will break up next week. When the proto works, if I license it, I charge extra for designing great casework, and someone else builds the proto of the casework for me to approve and for the factory to copy.
But these guys build one little amp in their lives, or two, and each one is like a baby to them. They dont have the culture and experience to know what a real orchestra sounds like in a good hall, so the glittering appearance of the amp is far more important to them than the sound. I build ten or twelve new designs a year, and dont have time to waste on anything but the sound. Developing the electronics is time-consuming enough. For instance, the T68bis Minus Zero that gave rise to this thread is the first of many 417A amps I built that worked perfectly at switch-on. You can spend weeks just getting the wire dress right on these RF tubes, but this time years of experience has, exceptionally, paid off instantly. (Notice how no one has congratulated me on it. These pretend-gurus are so ignorant about tubes that they dont even understand that something exceptional has happened.)
If Turner takes me up on my challenge to put this amp and the accompanying horns on his netsite for a year, you will have an opportunity to hear the imagination-challenged creepy-crawlies screech in outrage at the roughly finished, primered plywood board stiffening up the .042in Hammond case bottom plate on which I build an amp with probably three or four grands worth of components. Just for them I shall instead call it Pre-Distressed Aircraft Carrier Gun Metal Grey, and then listen to them ooh and aah.
They are all about appearances. No substance. No brains. No ideas. No balls to do anything except copy the safe old certainties. Boring, plodding, yech, a more stolidly built mousetrap. Their lack of originality would not be so bad if at least they had some style or grace or some other attractive characteristic, because not everyone can be a genius, but they are without exception exceptionally unattractive human beings too.
Andre Jute
Form@C
<snip>
>
> If Turner takes me up on my challenge to put this amp and the accompanying
> horns on his netsite for a year, you will have an opportunity to hear the
> imagination-challenged creepy-crawlies screech in outrage at the roughly
> finished, primered plywood board stiffening up the .042in Hammond case
> bottom plate on which I build an amp with probably three or four grands
> worth of components. Just for them I shall instead call it Pre-Distressed
> Aircraft Carrier Gun Metal Grey, and then listen to them ooh and aah.
>
<snip>
Nice one Andre! That's how they *should* be built - at first anyway!
I notice that my old links to your site are dead now... :-(
--
Mick
http://www.nascom.info for Nascom & Gemini information
Also at http://www.mixtel.co.uk where the collection started.
Currently deserting M$ for linux... :-)
Henry A. Pasternack
news:4afc1210171f8b77...@cryptorebels.net...
> My interest is in how the electronics work. I dont waste time and effort
> making beautiful fittings for an item I will break up next week. When
> the proto works, if I license it, I charge extra for designing great
> casework, and someone else builds the proto of the casework for me to
> approve and for the factory to copy.
I highly recommend the books of Wes Hayward, an American radio amateur
who has written a number of landmark DIY theory and practice books,
including "Solid State Design for the Radio Amateur", "Introduction to
Radio Frequency Design", and, most recently, "Experimental Methods in RF
Design." Wes is a big proponent of the "ugly" method of prototyping and
almost looks down on neat construction. I sent him a scan of an IF board
I was building last spring and I don't think he was too impressed.
Wes also has a website, by the way. Check it out:
http://users.easystreet.com/w7zoi/w7zoi-page.html
Anyway, whether you're building highly-refined finished products or
butt-ugly but innovative prototypes, why not give us a chance to judge
your work for ourselves? I'd like, for instance, to see exactly how
a master does the lead dress on a 417A.
Now, I know only complete plodders build pretty equipment, but you
might want to check out these amplifier pictures, which were posted
the other day on AudioAsylum:
http://audio-nirvana.fortunecity.net/img/jml6.jpg
http://audio-nirvana.fortunecity.net/img/jml5.jpg
Personally, Andre, I think you're full of hot air when it comes to all
the great work you claim to be doing. But if you can prove otherwise,
let's have it. As you said, "Put up or shut up!"
-Henry
Patrick Turner
> Now, I know only complete plodders build pretty equipment, but you
> might want to check out these amplifier pictures, which were posted
> the other day on AudioAsylum:
>
> http://audio-nirvana.fortunecity.net/img/jml6.jpg
> http://audio-nirvana.fortunecity.net/img/jml5.jpg
>
What is the tube line up?
What items reside under the round transformer covers?
Gotta schemo?
Patrick Turner.
Sander deWaal
> Now, I know only complete plodders build pretty equipment, but you
> might want to check out these amplifier pictures, which were posted
> the other day on AudioAsylum:
> http://audio-nirvana.fortunecity.net/img/jml6.jpg
> http://audio-nirvana.fortunecity.net/img/jml5.jpg
Did you build this one, Henry?
My dear, looks like I've got some work to do on my own amps .
I still have the protos running at home which got more holes in it
than a Swiss cheese.............not to mention the power transformers
that are lying loose on the chassis'. BAD PRACTICE, I know!
--
Sander deWaal
Vacuum Audio Consultancy
Henry A. Pasternack
news:4qghuv84rrisouq9t...@4ax.com...
> Mr Pasternack said:
>
> > Now, I know only complete plodders build pretty equipment, but you
> > might want to check out these amplifier pictures, which were posted
> > the other day on AudioAsylum:
>
> > http://audio-nirvana.fortunecity.net/img/jml6.jpg
> > http://audio-nirvana.fortunecity.net/img/jml5.jpg
>
> Did you build this one, Henry?
Oh, no! I've never tried to make anything that pretty (so far). I
don't have any more information on the amplifiers, but the parent
website looks pretty interesting. I'll have to check it out later,
after I get the kids to bed.
-Henry
Form@C
Don't you think its little things that make the difference to the
appearance? Things like the valve "skirts" and the "antique appearance"
instrument - things that ordinary mortals just can't get, at least for a
reasonable sum. It's bad enough just trying to get a bit of decent
metalwork without those trimmings. Guess why so many amps are built on
flat metal plates with a wooden surround? These bits add nothing to the
sound (anyone can build a really crap amp that has a very high "coolness"
factor just by throwing cash at the appearance), but a lot to the
perceived value of the product.
Concentrate on the music - leave the fancy bits to the marketing men! :-)
That amp is very pretty though... :-)
Henry A. Pasternack
news:pan.2003.12.24....@mixtel.co.uk...
> Don't you think its little things that make the difference to the
> appearance? Things like the valve "skirts" and the "antique appearance"
> instrument - things that ordinary mortals just can't get, at least for a
> reasonable sum. It's bad enough just trying to get a bit of decent
> metalwork without those trimmings. Guess why so many amps are built on
> flat metal plates with a wooden surround? These bits add nothing to the
> sound (anyone can build a really crap amp that has a very high "coolness"
> factor just by throwing cash at the appearance), but a lot to the
> perceived value of the product.
>
> Concentrate on the music - leave the fancy bits to the marketing men! :-)
> That amp is very pretty though... :-)
I agree. I try to make things look tidy, but I'm not going to spend
hundreds of dollars sending out to have custom chassis machined and
painted and lettered. If I had the tools to do it myself, though, I
would -- to a point. It isn't dignified to doll up an amplifier like
a French poodle. I like these KT-88 amps, though.
Speaking of poodles, it's interesting how anybody can become a tube
guru, now that knowledge of electronics is no longer a necessary --
or desirable -- trait in an audio designer. What do you think about
this guy?
-Henry
John Byrns
<hpast...@rcn.dot.com> wrote:
> "Form@C" <mi...@mixtel.co.uk> wrote in message
> > Concentrate on the music - leave the fancy bits to the marketing men! :-)
> > That amp is very pretty though... :-)
>
> I agree. I try to make things look tidy, but I'm not going to spend
> hundreds of dollars sending out to have custom chassis machined and
> painted and lettered. If I had the tools to do it myself, though, I
> would -- to a point. It isn't dignified to doll up an amplifier like
> a French poodle. I like these KT-88 amps, though.
>
> Speaking of poodles, it's interesting how anybody can become a tube
> guru, now that knowledge of electronics is no longer a necessary --
> or desirable -- trait in an audio designer. What do you think about
> this guy?
>
> http://www.electronluv.com/
I don't know about the guy, although it sound's like you have something
against him, but I sure like the looks of his amplifers, they are far
better looking than the ones at the last link you posted.
Regards,
John Byrns
Surf my web pages at, http://users.rcn.com/jbyrns/
Henry A. Pasternack
news:jbyrns-2412...@216-80-74-88.d.enteract.com...
> I don't know about the guy, although it sound's like you have something
> against him, but I sure like the looks of his amplifers, they are far
> better looking than the ones at the last link you posted.
In matters of taste, there is no dispute. However, IMHO, the amplifier
looks
like a robot poodle -- a perfect example of putting more work into the box
than into the electronics.
-Henry
Anonymous via the Cypherpunks Tonga Remailer
Andre Jute wrote:
<snip>
>
> If Turner takes me up on my challenge to put this amp and the accompanying
> horns on his netsite for a year, you will have an opportunity to hear the
> imagination-challenged creepy-crawlies screech in outrage at the roughly
> finished, primered plywood board stiffening up the .042in Hammond case
> bottom plate on which I build an amp with probably three or four grands
> worth of components. Just for them I shall instead call it Pre-Distressed
> Aircraft Carrier Gun Metal Grey, and then listen to them ooh and aah.
>
<snip>
"Form@C" <mi...@mixtel.co.uk> replied:
: Nice one Andre! Thats how they should be built - at first anyway!
Hell, I just painted this one because I was tired of the ali turning my hands black. If I still like it after a few months, Ill transfer it to a copper plate Ive been saving for a nice amp, and get a well-grained oak case made for it with oak a local woodworker is holding for me.
Heres a cheapie tip about boxing a flat-plate proto while you play it. Any second hand furniture shop has drawers out of furniture that no longer exists. Beg or buy a few. Turn upside down, cut hole to mount flat-plate proto (with all controls and connectors on top of flat plate, of course), bolt in flat plate, and now you have an open-bottom (cover with tacked on plasticized corrugated cardboard as used for posters by real estate agents) but otherwise pet- and child-safe proto ready for use.
I notice that my old links to your site are dead now... :-(
Pasternack and the rest of the Magnequest Scum worked for years to get it shut down. At one stage my ISP had 30 on the job of just sorting out which of their 200 complaints a day referred to their own fake letters about which they then complained, and which were actually my letters. Eventually, the ISP paid me to go away, because I was the most expensive customer they ever had.
I have a new toy, a Canon Ixus digital camera, and used it to document both the T68bis Minus Zero potato amp and the Twin-Channel HWAF Lowther Horns (1), with the photos downloading to my computer as I took them, so it would be no big deal to write an illustrated article. But I have no intention of putting up my netsite again merely to be a target for the bookburners and other slime on RAT, so, without a place for me to publish the article, Im sorry to disappoint you.
--
Mick
http://www.nascom.info for Nascom Gemini information
Also at http://www.mixtel.co.uk where the collection started.
Currently deserting M$ for linux... :-)
Perhaps the turneroid will take up my challenge to publish my amp and speakers on his netsite for one year, when we shall see which attracts more interest, his dull, mindlessly derivative crap or my amp and speakers.
Happy days.
Andre Jute
(1) Twin-Channel because they have a second smaller horn on top of the channel for the main horn to control resonances. HWAF stands for High Wife Acceptance Factor to indicate that their footprint is reasonable enough, as horns go, to be given space in a living room rather than merely in dedicated listening rooms. Lowther is the name of the manufacturer of the drivers.
Steve O'Neill
As you're no doubt aware, products of this designer have a cult following.
I've read discussions where someone may question some aspect of the design
or execution and the true believers (AKA owners) pounce all over him. I
for one will probably never get to draw my own conclusions about these
things since I live in a region of the US where objectivity and practicality
are valued, i.e nobody around here would carry them much less buy them.
I gather that Josh gets a lot of "help" with the actual electrical design
and he packages the result in his metal sculptures using only the finest
combination of vintage and new mfg components. He also seem to have a real
attraction to Hg rectifiers but I think it's more for show than anything
else; many of the images you see of the amps are shot with low level
lighting so the blue glow is really stands out.
To my eye, the amps ARE visually striking on first view. Over the long run
I think they would visually dominate the room they reside in with music
being secondary...maybe not a good thing. It also seems that new designs
are becoming variations on the theme begun with the original designs, as if
he's stuck in a design rut.
Regarding audio gurus not needing electronics knowledge, that situation has
been going on for years in hi-end audio. This is how we get audiophile
grade power outlets, photon shielded interconnects and beeswax caps etc.
etc. etc....but I'm sure you already knew that too.
Overall, I think electronluv is a great example of what can happen in a
capitalist/consumerist environment. Every little market niche gets served.
I wish him continued success although I won't be contributing to it.
--
Steve
John Stewart
The 826/2A3 amp on that site is one of the poorest I've ever seen.
The schematic drawing is even worse. The whole thing is the work of
an amatuer. Why anyone would pay $$$$$ for that crap is a mystery.
Is that site a joke or what?
So there!! John Stewart
John Stewart
John Byrns wrote:
John- Did the Norman Crowhurst article I emailed to you direct covering
optimizing & stabilizing of the amplifier feedback get to you OK &
have you had an opportunity to review it?
Cheers, John Stewart
Yves Monmagnon
"John Stewart" <jh.st...@sympatico.ca> wrote in message
news:3FE9B1A7...@sympatico.ca...
> "Henry A. Pasternack" wrote:
>
....................;
> >
> > http://www.electronluv.com/
> >
> > -Henry
>
> The 826/2A3 amp on that site is one of the poorest I've ever seen.
> The schematic drawing is even worse. The whole thing is the work of
> an amatuer. Why anyone would pay $$$$$ for that crap is a mystery.
Sometimes they match ;>)
> Is that site a joke or what?
>
> So there!! John Stewart
>
>
>
>
Henry A. Pasternack
news:OChGb.524054$0v4.22...@bgtnsc04-news.ops.worldnet.att.net...
> Overall, I think electronluv is a great example of what can happen in a
> capitalist/consumerist environment. Every little market niche gets
served.
> I wish him continued success although I won't be contributing to it.
Yes, I have nothing against him or his venture. I don't know what to say
about the judgment of his customers. But if they have the money to throw
away on thoriated tungsten poodles, it's their free choice.
-Henry
John Stewart
Perhaps there is a market for non-functional vacuum tube lookalikes.
Then it would be possible for these imposters to build their works of
art & simply conceal a SS module inside to make the noise.
Might even improve the profit margin.
That would also help conserve the ever dwindling supply of tubes
for real applications. Cheers, John Stewart
>
> >
> >
> >
> >
Henry A. Pasternack
in message news:3fe3b47615c40533...@cypherpunks.to...
> I have a new toy, a Canon Ixus digital camera, and used it to document
> both the T68bis Minus Zero potato amp and the Twin-Channel HWAF Lowther
> Horns (1), with the photos downloading to my computer as I took them, so
> it would be no big deal to write an illustrated article. But I have no
> intention of putting up my netsite again merely to be a target for the
> bookburners and other slime on RAT, so, without a place for me to publish
> the article, Im sorry to disappoint you.
If you actually had something worthwhile to share, and the desire to share
it, you would. I choose to believe your projects are either vaporware or
garbage. Prove me wrong.
Remember the ill-fated Lundahl schematics? That was a laugh.
Say, where's that book on the modular amplifier series you were writing?
Did you refund Lundahl for the components he sent you, since you never
delivered the book? He probably doesn't want them back now that you've
melted all the terminals off with your butane-powered soldering iron.
Oh well! Merry Christmas!
-Henry
Form@C
<snip>
>
> Speaking of poodles, it's interesting how anybody can become a tube guru,
> now that knowledge of electronics is no longer a necessary -- or desirable
> -- trait in an audio designer. What do you think about this guy?
>
> http://www.electronluv.com/
>
mm.... In its own right its art, but does it make music? Without hearing
it, who knows? Not really my cup of tea, but then again, I'm not a
metalwork sculptor. The mercury recs are pretty but I don't think they
would be a big selling point to me. Far too fussy!
I, personally, wouldn't class that stuff as "tube guru" gear. I don't have
the knowledge and experience with real "hi-fi" valve stuff but I think his
power supplies look over-complex. 3 regs in a row to feed filaments? Why
not get the right mains tranny in the first place & get rid of the
regulator noise by not creating it in the first place? It doesn't fill me
with confidence... Too many chokes too.
Anonymous
> http://www.electronluv.com/
>
> -Henry
The 826/2A3 amp on that site is one of the poorest Ive ever seen.
The schematic drawing is even worse. The whole thing is the work of
an amatuer. Why anyone would pay $$$$$ for that crap is a mystery.
Is that site a joke or what?
So there!! John Stewart
- - - - - -
Perhaps those amps are more about lifestyle than music. Each to his own. I agree with John Byrns, at least these look more interesting than the first amp Pasternack posted reference to (1), and I also agree with Steve that every niche gets served and who are we to cavil, as long as we dont actually spend our own money on the mans products.
Andre Jute
(1) Ive actually built something like this amp, though with fewer pieces of glass, and the round bits painted in the same maroon as the base, but I cant say I liked it much after the initial lookmahowcleverIam phase wore off. Toroids are no more intrinsically interesting than rectangular boxes for transformers. My present project, the T68bis Minus Zero has all the tubes inside the box. Tubes on display are for newbies and ostentatious consumers. Adult music lovers have no need of such vulgar display. . . .
. . . . Well, of course the real reason is that the two 417A, which are less than three-quarters of an inch long, look miserable on the aircraft carrier expanse of so much iron under the deck, and against even a small rectifier like the GZ34, indeed even against the much a nine-pin rectifier like the EZ81. Even if I boxed the monstrous iron I use to guarantee an utterly silent amp, the tubes would look like little splotches of light against them, too bizarre for words. Even the rubber doughnuts I use to mount the chokes come halfway up the height of the 417A. . . .
John Stewart
Just took a look at the so-called '10 Amp' on that site.
I would be ashamed to put my name on a schematic of that caliber.
Another useless piece of dog excrement.
Hard to believe anyone would pay someone to screw things
up so terribly. This buz has far too much smoke & mirrors. And BS.
Where is Josh Stippich? Would he come forward to defend his circuitry?
Not too damned likely. There are too many of the gullible out there most
willing to part with their bucks for a piece of glass & chrome that probably
sounds like shit, even when powered by a $300.00 line cord.
Pity, John Stewart
John Byrns
Yes, I did receive it, and have read it twice through, I will try to post
a review of the article within the next day or two.
Form@C
Remailer wrote:
<snip>
>
> Heres a cheapie tip about boxing a flat-plate proto while you play it. Any
> second hand furniture shop has drawers out of furniture that no longer
> exists. Beg or buy a few. Turn upside down, cut hole to mount flat-plate
> proto (with all controls and connectors on top of flat plate, of course),
> bolt in flat plate, and now you have an open-bottom (cover with tacked on
> plasticized corrugated cardboard as used for posters by real estate
> agents) but otherwise pet- and child-safe proto ready for use.
>
Yep - I like that idea!
<snip>
>
> I have a new toy, a Canon Ixus digital camera, and used it to document
> both the T68bis Minus Zero potato amp and the Twin-Channel HWAF Lowther
> Horns (1), with the photos downloading to my computer as I took them, so
> it would be no big deal to write an illustrated article. But I have no
> intention of putting up my netsite again merely to be a target for the
> bookburners and other slime on RAT, so, without a place for me to publish
> the article, Im sorry to disappoint you.
Very sad... I thought your site was a good read!
Incidentally, although I generally agree with your ideas about low power
amps, I'm not sure that my Mrs would take to Lowther-Voights either. You
may be onto something if your design is trulu HWAF!
A pretty link: http://my.execpc.com/~n9zes/speakers.htm
--
Mick
http://www.nascom.info for Nascom & Gemini information
John Byrns
<an...@anon.itys.net> wrote:
> Re: I would like to see pictures of Andres projects.
> rec.audio.tubes
>
> > http://www.electronluv.com/
> >
> > -Henry
>
> The 826/2A3 amp on that site is one of the poorest Ive ever seen.
> The schematic drawing is even worse. The whole thing is the work of
> an amatuer. Why anyone would pay $$$$$ for that crap is a mystery.
> Is that site a joke or what?
>
> So there!! John Stewart
>
>
> - - - - - -
>
> Perhaps those amps are more about lifestyle than music. Each to his own. I
> agree with John Byrns, at least these look more interesting than the first
> amp Pasternack posted reference to (1), and I also agree with Steve that
> every niche gets served and who are we to cavil, as long as we dont actually
> spend our own money on the mans products.
>
> Andre Jute
> (1) Ive actually built something like this amp, though with fewer pieces of
> glass, and the round bits painted in the same maroon as the base, but I cant
> say I liked it much after the initial lookmahowcleverIam phase wore off.
> Toroids are no more intrinsically interesting than rectangular boxes for
> transformers. My present project, the T68bis Minus Zero has all the tubes
> inside the box. Tubes on display are for newbies and ostentatious consumers.
> Adult music lovers have no need of such vulgar display. . . .
As a compromise position it is hard to beat a pair of the original metal
6L6s, driven by 6SJ7 or similar tube of your choice. Exposed tubes
without the ostentation.
John Stewart
Another thought has to do with safety. No way these abortions would pass
UL, CSA or regulatory body in any country. Well, maybe North Korea!!
Cheers, John Stewart
Form@C
<snip>
>
> Now, I know only complete plodders build pretty equipment, but you might
> want to check out these amplifier pictures, which were posted the other
> day on AudioAsylum:
>
> http://audio-nirvana.fortunecity.net/img/jml6.jpg
> http://audio-nirvana.fortunecity.net/img/jml5.jpg
>
Yowee! I've been having a look at that web site. That is a mono amp, 6x
KT88s on the output, 70 watts in triode & 120 watts in tetrode. Its a
prototype. http://audio-nirvana.fortunecity.net/pag_eng/frames_eng.htm
He's done a lovely job...
John Stewart
They could be Hammond 125E's which do a reasonable job at a
very good cost. Would easily fit under those large covers & set in
place by potting. Many people who listen to these boutique designer
amps would probably be unable to detect a difference anyway.
Or, if the design is for real there could be Plitrons under the hood.
Who knows!!!!!!!!! John Stewart
>
>
> Gotta schemo?
>
> Patrick Turner.
Jon Yaeger
Henry A. Pasternack
news:4ff96f9ce2c2b168...@itys.net...
> Perhaps those amps are more about lifestyle than music. Each to his own.
> I agree with John Byrns, at least these look more interesting than the
first
> amp Pasternack posted reference to (1), and I also agree with Steve that
> every niche gets served and who are we to cavil, as long as we dont
> actually spend our own money on the mans products.
Well, at least he should get credit for actually producing products and
releasing them to the public, something you only dream about.
Sweet dreams, Andre.
-Henry
Greg Pierce
enlightened us with these pearls of wisdom:
I agree - it is horrible. The 2.5H input choke for the 2A3 is barely
adequate (total load for 2 channels is 120mA) to keep the merc vape
rectifiers operating in CC mode. Speaking of mercs, they can be
noisy, and I see NO line-side noise filters. It should have small-value
noise decoupling caps near the rectifiers as well. Personally, I
wouldn't use mercs - I would use vacuum rectifiers (my fave) or FREDS.
All in all, this design is total garbage, but then most of these "guru"
SE jobs are a joke. Someone needs to teach these pukes how to
design a proper SE amplifier...
--
Greg
Disgusted
Greg Pierce
enlightened us with these pearls of wisdom:
> Patrick Turner wrote:
They are probably Plitrons...
BTW, for those of you who use SPICE to design tube amps, here is my
Christmas present: The SPICE model for the Plitron PAT-4142-00
* PLITRON PAT-4142-00 OUTPUT TRANSFORMER 4KOHM UL PRIMARY
* 33% UL TAP RATIO - 4/8/16 OHM SECONDARY TAPS - 70 WATTS
*
* 16 OHM SECONDARY TAP -------------|
* 8 OHM SECONDARY TAP ------------| |
* 4 OHM SECONDARY TAP ----------| | |
* COMMON SECONDARY TAP -------| | | |
* LOWER PLATE --------------| | | | |
* LOWER UL TAP -----------| | | | | |
* CENTER TAP ---------| | | | | | |
* UPPER UL TAP -------| | | | | | | |
* UPPER PLATE ------| | | | | | | | |
* | | | | | | | | |
.SUBCKT PAT-4142-00 1 2 3 4 5 6 7 8 9
*
LP1 1 10 111.7761
LP2 2 11 27.1161
LP3 3 12 27.1161
LP4 4 13 111.7761
LS1 6 14 1.010376025
LS2 7 15 0.166382027
LS3 8 16 0.334401466
RLP1 10 2 26.13
RLP2 11 3 12.87
RLP3 12 4 12.87
RLP4 13 5 26.13
RLS1 14 7 0.11
RLS2 15 8 0.09
RLS3 16 9 0.08
CP 1 5 1n
KALL LP1 LP2 LP3 LP4 LS1 LS2 LS3 .999993976
.ENDS PAT-4142-00
--
Greg
--The software said it requires Win2000 or better, so I installed Linux.
Don
says...
or alt.binaries.schematics.electronics, which he could easily do and still
hide behind re-mailers.
2.) Andre doesn't put up a wwebsite on any free web sites, such as
http://geocities.yahoo.com/, which allows 25 mbytes free space.
Maybe Andre has nothing to show us.
Form@C
<snip>
> 1.) Andre doesn't anonymously post any pictures to
> alt.binaries.pictures.radio or alt.binaries.schematics.electronics, which
> he could easily do and still hide behind re-mailers.
>
> 2.) Andre doesn't put up a wwebsite on any free web sites, such as
> http://geocities.yahoo.com/, which allows 25 mbytes free space.
>
Actually, 15MB on the free pages...
> Maybe Andre has nothing to show us.
I hope Andre sees this...
This is, of course, possible. Andre? Would you like to email me (anon,
of course) some piccies? I'll put them up, uncommented, under my details,
on a free Yahoo site for you if you want - and providing that I can get
this linux box to do what I want! That way they can't be traced back.
Your viewers will just have to put up with the adverts! No hard feelings
if you don't want to do this. I'm just trying to help protect your privacy.
--
Mick
http://www.nascom.info for Nascom & Gemini information
Jeff S 386 Fla
Form@C
> I'd like to see pictures of your sister naked
why? Is she of the single-ended triode persuasion? Or maybe push-pull is
more her style?
:-)
John Byrns
> John- Did the Norman Crowhurst article I emailed to you direct covering
> optimizing & stabilizing of the amplifier feedback get to you OK &
> have you had an opportunity to review it?
John, I assume the reason you emailed me the copy of this Crowhurst
article was because I asked why when you said that lead compensation was
bad. Unfortunately this article doesn't answer the question, beyond
making it obvious that you are not alone in your opinion, and that
Crowhurst didn't like it either. The article is not a technical article
written to explain the theory of negative feedback, and the evils of lead
compensation as applied to audio amplifiers, but rather is written for the
audio hobbyist who wants to muck around with the feedback parameters of
his amplifier, ostensibly to make it "better". There is no theory
presented, only a little how to, without even any discussion of the
tradeoffs that might be involved in making the suggested changes.
Henry Pasternack would probably be a better person to review this article
as he has spent some time studying the theory of negative feedback as
applied to audio amplifiers. But I will give it a go in a general sense.
One of Crowhurst's early premises in the article is that lead compensation
is not good and results in degraded sound quality, and is only used in the
first place to get good specs from the amplifier into a resistive load.
He suggests removing any lead compensation in the amplifier, and using
only lag compensation. He fails to provide any meaningful argument as to
exactly what is wrong with lead compensation, and why it degrades the
sound of an amplifier. All he really ends up saying is that speakers
present an inductive load to the amplifier, and when an amplifier is
operated into an inductive load the open loop response will change from
what it is when operated into a resistive load. OK, but he doesn't make
any attempt at a case for why this should have a negative impact on the
sound. Even making the hypothetical assumption that inductive loads are a
problem when lead compensation is used, he fails to discuss alternatives
that might mitigate any possible problem, such as using Zobel networks
across the output. His whole attitude, and lack of explanation, with
respect to lead compensation makes me nervous because most well designed
modern amplifiers seem to use a combination of both lag and lead
compensation, plus Zobel networks, so he really needs to make a case for
marching to a different drummer. I have even read articles that take the
opposite tack, and claim that over reliance on lag compensation can
degrade an amplifiers sound, and I think the articles I have seen in that
vein have made a better case their point of view than Crowhurst does.
I was also concerned with his recommendations for changing the low
frequency time constants, not so much from a theoretical point of view,
but from the practical point of view, in that he doesn't give any
discussion of the design compromises that may have been necessary in the
first place. In particular given an amplifier with a low cost output
transformer, it may be necessary to increase the time constant of some of
the coupling capacitors to meet Crowhurst's stability criterion. While
this may provide optimum low frequency feedback stability, it may also
result in other new problems. I would think he should have discussed the
possible addition of an infrasonic high pass filter at the input to the
amplifier to head off problems resulting from the modified time constants,
or the original ones for that matter.
The bottom line is that I feel the Crowhurst article is essentially
useless without at least a sketchy discussion of the theory involved, some
real justification for the position taken, and a complete review of the
design tradeoffs that may have originally been made in the amplifier, and
how the suggested changes may affect those tradeoffs, and the performance
consequences for the amplifier.
I have a 1930s do it your self article on applying negative audio feedback
to broadcast transmitters, written by Western Electric, who I believe
invented "negative feedback", which I will have to dig out for a
comparison read. This was a similar how to article explaining how to
stabilize a transmitter at the low and high frequencies after applying
negative audio feedback from a rectifier connected to the antenna output,
back to the audio input stage. The typical broadcast transmitter in the
1930s was modulated at a low level, so this sort of feedback was feasible,
and I believe the situation is generally comparable to our situation with
audio amplifiers. Later broadcast transmitters used high level
modulation, and it was not possible to apply feedback across the
modulation transformer, so feedback was only used over the audio stages,
from the plates of the modulator tubes back to the input circuits.
Henry, what do you think about all this, have you read the Crowhurst
article in question? Is lead compensation really the sonic evil that
Crowhurst and Stewart say it is? If it is, do you have any thoughts on
why it is?
Rich Andrews
@sympatico.ca:
Ick! Real Ick!
r
--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.
Rich Andrews
news:20031225142924...@mb-m15.aol.com:
> I'd like to see pictures of your sister naked
You really don't mean that. If you were serious, you would be one sick
puppy.
Sander deWaal
>I have a 1930s do it your self article on applying negative audio feedback
>to broadcast transmitters, written by Western Electric, who I believe
>invented "negative feedback", which I will have to dig out for a
>comparison read.
NFB: Harold Black, 1926.
PFB: Meissner, ca. 1914.
--
Sander deWaal
Vacuum Audio Consultancy
Henry A. Pasternack
news:jbyrns-2512...@216-80-74-111.d.enteract.com...
> Henry, what do you think about all this, have you read the Crowhurst
> article in question? Is lead compensation really the sonic evil that
> Crowhurst and Stewart say it is? If it is, do you have any thoughts on
> why it is?
I haven't seen the article, and it sounds as though I'm not missing too
much. If you want to forward a copy to me I'd be interested to see what
it has to say.
I know the theory of negative feedback has been well understood for ages,
but I gather there's been a lot of progress on its applications in the last
twenty years or so. You can imagine how critical this is for applications
like computer-controlled manufacturing, aircraft fly-by-wire systems, and
so on.
Anyway, lead compensation is a useful tool, and like any tool, it can be
used improperly, leading to a mess. I can't imagine why lead compensation,
properly applied in the context of a thoughtfully designed feedback circuit,
would produce audible problems.
-Henry
John Stewart
Crowhurst article this AM. Cheers, John Stewart
Henry A. Pasternack
the size reduction of the scan. But I think I understand what Crowhurst
is on to.
If you look at a lot of vintage tube amplifier schematics, they have no
lag compensation whatsoever in the forward path (the Williamson is an
exception). Such an amplifier, with a resistive load, will have a
dominant pole at, say 30kHz due to the rolloff of its (typically mediocre)
output transformer. A single phase-lead capacitor across the feedback
resistor will correct for one additional pole, and with, say, 20dB of
feedback the amplifier will reach unity-gain crossover at 300kHz, more
or less, without excessive phase shift. In this configuration, it will
be quite stable.
Now, if you hang an inductor on the output (or open-circuit the load),
the dominant pole disappears and suddenly the amplifier is effectively
uncompensated. Worse, the lead compensation capacitor (which also
introduces a pole at a very high frequency) extends the loop frequency
response out to the point where a slew of uncontrolled response poles
and tranny resonances come into play. So the amplifier is fine on the
test bench, but oscillates driving a real-world load. I've seen this
myself and the effect is clearly audible and unpleasant.
Crowhurst describes a scheme for lag compensating the amplifier. I
haven't had time to work through it to verify the theoretical basis of
his method. It's true, if you lag compensate an amplifier heavily
enough, that it will be unconditionally stable without any phase lead
correction. But you can get more feedback at high frequencies, lower
distortion, and better transient response if you do lag-lead compensation.
The "speedup" capacitor across the feedback resistor is a useful tool,
and it also helps protect the amplifier against TIM (if that's an issue,
which it shouldn't be).
Overall, I would say Crowhurst has identified a valid problem, but done
a bad job of explaining what it is or how to solve it, and incorrectly
assigns blame to the phase lead capacitor. The real culprit is just
bad feedback loop design.
-Henry
John Byrns
Hi Henry,
Thanks for the comments, they match my thinking point for point, except
the one crucial point that I missed, and which presumably explains where
the trouble comes in. The point you bring up, which I missed, and that I
think is the answer to the puzzle is your statement that "Worse, the lead
compensation capacitor (which also introduces a pole at a very high
frequency) extends the loop frequency response out to the point where a
slew of uncontrolled response poles and tranny resonances come into
play." I missed the "slew of uncontrolled response poles and tranny
resonances", which I assume are the root of the problem.
I am especially grateful for the comment on TIM because back during the
big TIM scare in the seventies, IIRC and of course I may not, several
authors suggested that over reliance on lag compensation could lead to TIM
problems, and the use of lead compensation, in addition to lag
compensation, was a weapon in the fight against TIM.
I found Crowhurst's article totally ambiguous as to what he was getting
at, because while his example circuit showed only lead compensation, in
the text he said to "remove the phase-shift capacitors, particularly the
one across the feedback resistor if one is used at that point." The
phraseology implied that there were other compensation capacitors,
presumably lag compensation capacitors, to be removed in addition to the
capacitor across the feedback resistor. Additionally the article was
written in 1957, just at the time I was getting interested in Hi-Fi, and
the Heathkit amplifiers I built at the time included lag compensation
networks in addition to the lead compensation capacitor across the
feedback resistor.
In addition to the ambiguity of the types of amplifier circuitry he was
talking about, it seemed to me that the inductive load problem could also
be dealt with by adding a Zobel network across the output.
I suspect the best solution would have been to use a combination of all
three methods. It is my feeling that the advice given in this article is
not the best advice, and the contemporary audiophile would be wise to take
a more reasoned and balanced approach.
Regards,
John Byrns
In article <3fef82f6$0$4753$61fe...@news.rcn.com>, "Henry A. Pasternack"
<hpast...@rcn.dot.com> wrote: