I want to build a tube power amp for my stereo. Tubes have always had
the best sound. Actually two amps, one for each channel. First off,
what tubes can I use in Push-Pull Parallel to achieve at least 1000
watts RMS per channel. I want real power. Not peak to peak, but true
RMS. Secondly, where can I obtain the output transformers, or will I
have to have them custom made, and where?

When I was much younger I had two amps that used 4 6L6 tubes in
push-pull parallel and I was able to achieve about 120 watts per
channel. The sound was great, but 6L6 tubes have their limits on
power, and tend to be noisy (at least the old ones did, as I had to
shock mount the amps to prevent feedback thru the tubes.

Going with 1000 watts, I will need much more control and tubes that
can handle the abuse. In reality, I'd like to go for 2500 or even
5000 watts per channel, but I doubt any tubes can handle that.

On the other hand. the thought arises to build 4 of these amps, use
two for the low end, and the other two for the horns. I assume that
for the horns I could cut back some on the power output, but need
everything I can get for the bass end, since I intend to build a wall
of 16 inch woofers.

Thanks for all help.

Mark

On May 11, 8:04 pm, wrote:
I want to build a tube power amp for my stereo. Tubes have always had
the best sound. Actually two amps, one for each channel. First off,
what tubes can I use in Push-Pull Parallel to achieve at least 1000
watts RMS per channel. I want real power. Not peak to peak, but true
RMS. Secondly, where can I obtain the output transformers, or will I
have to have them custom made, and where?

When I was much younger I had two amps that used 4 6L6 tubes in
push-pull parallel and I was able to achieve about 120 watts per
channel. The sound was great, but 6L6 tubes have their limits on
power, and tend to be noisy (at least the old ones did, as I had to
shock mount the amps to prevent feedback thru the tubes.

Going with 1000 watts, I will need much more control and tubes that
can handle the abuse. In reality, I'd like to go for 2500 or even
5000 watts per channel, but I doubt any tubes can handle that.

On the other hand. the thought arises to build 4 of these amps, use
two for the low end, and the other two for the horns. I assume that
for the horns I could cut back some on the power output, but need
everything I can get for the bass end, since I intend to build a wall
of 16 inch woofers.

Thanks for all help.

Mark

For that kind of power you will find it difficult, if not impossible,
to achieve your goals. All kinds of things will be unobtainable at
the extreem high power you are talking about..
**output transformers.... for sure ... if you could get them they
would weigh several hundred pounds each.

**power transformers and power supply ... several amps at 800 - 1200
volts or more ! ! expensive and hard to do.

**output tubes... even with push pull- parrallel ( 4 tubes) you will
have trouble getting anything close to 1000 watts with audiophile
tubes. You would probably have to use really expensive RF power
tubes which in all likely-hood will not be power pentodes and will
require serious drive power which at your desired power level would be
a problem for even "normal" high power audio output tubes.... then,
where would you get the high power interstage transformers.

All of these things will be most likely an exercise in futility.
My advice to you is to stick with solid state for you desired very
high power requirements.... there are several brands of readymade
1000 watt plus (many units can be bridged to increase power)
professional solid state amplifiers available that would be hard to
beat the price even if you built it yourself.
electricitym

In article ,
wrote:
Going with 1000 watts, I will need much more control and tubes that
can handle the abuse. In reality, I'd like to go for 2500 or even
5000 watts per channel, but I doubt any tubes can handle that.

The main interest in valves these days is with SET (single ended
transformer) designs which are the best for that 'valve sound'. And by
nature low powered so need sensitive speakers.

However, all is not lost. Simply use one of those driving a suitable
inductive load then feeding a decent high power solid state design. The
valve amp will give you all the distortion of the type you crave and the
SS one amplify it.

--
*To err is human. To forgive is against company policy.

Dave Plowman London SW
To e-mail, change noise into sound.

wrote in message
...
I want to build a tube power amp for my stereo. Tubes have always had
the best sound. Actually two amps, one for each channel. First off,
what tubes can I use in Push-Pull Parallel to achieve at least 1000
watts RMS per channel. I want real power. Not peak to peak, but true
RMS. Secondly, where can I obtain the output transformers, or will I
have to have them custom made, and where?

When I was much younger I had two amps that used 4 6L6 tubes in
push-pull parallel and I was able to achieve about 120 watts per
channel. The sound was great, but 6L6 tubes have their limits on
power, and tend to be noisy (at least the old ones did, as I had to
shock mount the amps to prevent feedback thru the tubes.

Going with 1000 watts, I will need much more control and tubes that
can handle the abuse. In reality, I'd like to go for 2500 or even
5000 watts per channel, but I doubt any tubes can handle that.

On the other hand. the thought arises to build 4 of these amps, use
two for the low end, and the other two for the horns. I assume that
for the horns I could cut back some on the power output, but need
everything I can get for the bass end, since I intend to build a wall
of 16 inch woofers.

Thanks for all help.

Mark

Is this a joke? 1KW from a tube amp? What do you plan on using for output
transformers? Hope you have a forklift to move them around and a very large
electrical service to power it all. It would eliminate the need for central
heating in your house as well.

In article ,
wrote:

I want to build a tube power amp for my stereo. Tubes have always had
the best sound. Actually two amps, one for each channel. First off,
what tubes can I use in Push-Pull Parallel to achieve at least 1000
watts RMS per channel. I want real power. Not peak to peak, but true
RMS.

Secondly, where can I obtain the output transformers, or will I
have to have them custom made, and where?

When I was much younger I had two amps that used 4 6L6 tubes in
push-pull parallel and I was able to achieve about 120 watts per
channel. The sound was great, but 6L6 tubes have their limits on
power, and tend to be noisy (at least the old ones did, as I had to
shock mount the amps to prevent feedback thru the tubes.

Going with 1000 watts, I will need much more control and tubes that
can handle the abuse. In reality, I'd like to go for 2500 or even
5000 watts per channel, but I doubt any tubes can handle that.

It used to be done all the time. While in college, I babysat an RCA
BTA-50F1 (almost the last of the plate-modulated 50 kilowatt AM
transmitters). The modulator delivered a cool 25,000 watts of tolerably
clean audio. The transmitter was on the second floor; the entire first
floor was the plenum for the blowers.

I suggest you look for a couple of old AM broadcast transmitters, and
extract the modulation transformers and audio circuits, for a good
starting place.

Then, I suggest that you learn exactly what the performance differences
are between tube and solid state amplifiers. Pay special attention to
what those output transformers do to the frequency and phase response.

Prepare to rewire your listening room, too, because if you don't,
there's no way you're getting a kilowatt -- much less a stereo pair of
kilowatts -- of output from a tube amp connected to a normal outlet.
With a switchmode solid-state job and special attention to efficiency,
maybe.

Isaac

On Sat, 12 May 2007 18:37:05 GMT, "James Sweet"
wrote:


wrote in message
.. .
I want to build a tube power amp for my stereo. Tubes have always had
the best sound. Actually two amps, one for each channel. First off,
what tubes can I use in Push-Pull Parallel to achieve at least 1000
watts RMS per channel. I want real power. Not peak to peak, but true
RMS. Secondly, where can I obtain the output transformers, or will I
have to have them custom made, and where?

When I was much younger I had two amps that used 4 6L6 tubes in
push-pull parallel and I was able to achieve about 120 watts per
channel. The sound was great, but 6L6 tubes have their limits on
power, and tend to be noisy (at least the old ones did, as I had to
shock mount the amps to prevent feedback thru the tubes.

Going with 1000 watts, I will need much more control and tubes that
can handle the abuse. In reality, I'd like to go for 2500 or even
5000 watts per channel, but I doubt any tubes can handle that.

On the other hand. the thought arises to build 4 of these amps, use
two for the low end, and the other two for the horns. I assume that
for the horns I could cut back some on the power output, but need
everything I can get for the bass end, since I intend to build a wall
of 16 inch woofers.

Thanks for all help.

Mark

Is this a joke? 1KW from a tube amp? What do you plan on using for output
transformers? Hope you have a forklift to move them around and a very large
electrical service to power it all. It would eliminate the need for central
heating in your house as well.


No, not a joke. I have wanted all my life to build a stereo that
handles the same power levels as a live concert. I'm now retired and
want to finally do it. Back when I was in my 20's I built my rather
crude system which consisted of 3 separate amplifiers, each putting
out 120Watts RMS, with 4 6L6 tubes in PPP. (The 3rd amp was a
"center" or combined channel that drove a bank of woofers). My huge
speaker towers that I built with one inch thick plywood, held guitar
amp speakers and horns. The power was amazing, but not quite as clean
as I wanted it, and that feedback thru the tubes was always a problem.
Once, when I was rather messed up (I'll skip the details), I cranked
it wide open and blew all the windows out of my apartment (the
landlord was NOT pleased). I attribute the window shattering to low
end distortion, (in a much too small apartment).

Now, I live on a farm and I want to fill the whole farm with
"live-like" sound. I guess you could call it my personal "Woodstock"
(ya, I'm showing my age). Actually handling hundred (or more) pound
transformers/amps would not be a problem, since I actually DO have
tractors and such to move them. but getting the xformers probably is.
I have 400AMP service at my panel, so I got enough power too.

However, I will consider using solid state amps if I can achieve the
right sound. I would imagine I could get some ready made PA system
amps. I used to know a guy that worked for a sound company that did
all the sound for major rock concerts. I know for fact that they had
the capability to run 10,000 watts total, and in most places used the
full amount at outdoor concerts. So, myself wanting to run at least
2000watts total is not too much to ask.

I'm curious why you think this is a joke? I'm asking because there
was a time when everything was tube. What did they use back then for
large concerts and auditoriums for the main system? Ya, I know that
the concerts back in those days were not as large as they have been
since the late 60's. I'm curious what they used at Woodstock, since
that was more or less the first concert of it's size, and that was
during the transition from tube to semi-conductors, and I know that
semi-con... power amps back in those days were prone to failure.

There seems to be a lot of historical information about Woodstock and
other major concerts back in the 60's and 70's, but finding details
such as the type of power amps used to supply the main system just is
not documented.

Mark

On Sat, 12 May 2007 09:27:13 +0100, "Dave Plowman (News)"
wrote:

In article ,
wrote:
Going with 1000 watts, I will need much more control and tubes that
can handle the abuse. In reality, I'd like to go for 2500 or even
5000 watts per channel, but I doubt any tubes can handle that.

The main interest in valves these days is with SET (single ended
transformer) designs which are the best for that 'valve sound'. And by
nature low powered so need sensitive speakers.

However, all is not lost. Simply use one of those driving a suitable
inductive load then feeding a decent high power solid state design. The
valve amp will give you all the distortion of the type you crave and the
SS one amplify it.

I'm not real familiar with this. Is there a website with details and
possibly schematics or at least detailed drawings? This might be just
what I am looking for.

Thanks

Mark

wrote in message
news
On Sat, 12 May 2007 18:37:05 GMT, "James Sweet"
wrote:


wrote in message
. ..
I want to build a tube power amp for my stereo. Tubes have always had
the best sound. Actually two amps, one for each channel. First off,
what tubes can I use in Push-Pull Parallel to achieve at least 1000
watts RMS per channel. I want real power. Not peak to peak, but true
RMS. Secondly, where can I obtain the output transformers, or will I
have to have them custom made, and where?

When I was much younger I had two amps that used 4 6L6 tubes in
push-pull parallel and I was able to achieve about 120 watts per
channel. The sound was great, but 6L6 tubes have their limits on
power, and tend to be noisy (at least the old ones did, as I had to
shock mount the amps to prevent feedback thru the tubes.

Going with 1000 watts, I will need much more control and tubes that
can handle the abuse. In reality, I'd like to go for 2500 or even
5000 watts per channel, but I doubt any tubes can handle that.

On the other hand. the thought arises to build 4 of these amps, use
two for the low end, and the other two for the horns. I assume that
for the horns I could cut back some on the power output, but need
everything I can get for the bass end, since I intend to build a wall
of 16 inch woofers.

Thanks for all help.

Mark

Is this a joke? 1KW from a tube amp? What do you plan on using for output
transformers? Hope you have a forklift to move them around and a very
large
electrical service to power it all. It would eliminate the need for
central
heating in your house as well.


No, not a joke. I have wanted all my life to build a stereo that
handles the same power levels as a live concert. I'm now retired and
want to finally do it. Back when I was in my 20's I built my rather
crude system which consisted of 3 separate amplifiers, each putting
out 120Watts RMS, with 4 6L6 tubes in PPP. (The 3rd amp was a
"center" or combined channel that drove a bank of woofers). My huge
speaker towers that I built with one inch thick plywood, held guitar
amp speakers and horns. The power was amazing, but not quite as clean
as I wanted it, and that feedback thru the tubes was always a problem.
Once, when I was rather messed up (I'll skip the details), I cranked
it wide open and blew all the windows out of my apartment (the
landlord was NOT pleased). I attribute the window shattering to low
end distortion, (in a much too small apartment).

Now, I live on a farm and I want to fill the whole farm with
"live-like" sound. I guess you could call it my personal "Woodstock"
(ya, I'm showing my age). Actually handling hundred (or more) pound
transformers/amps would not be a problem, since I actually DO have
tractors and such to move them. but getting the xformers probably is.
I have 400AMP service at my panel, so I got enough power too.

However, I will consider using solid state amps if I can achieve the
right sound. I would imagine I could get some ready made PA system
amps. I used to know a guy that worked for a sound company that did
all the sound for major rock concerts. I know for fact that they had
the capability to run 10,000 watts total, and in most places used the
full amount at outdoor concerts. So, myself wanting to run at least
2000watts total is not too much to ask.

I'm curious why you think this is a joke? I'm asking because there
was a time when everything was tube. What did they use back then for
large concerts and auditoriums for the main system? Ya, I know that
the concerts back in those days were not as large as they have been
since the late 60's. I'm curious what they used at Woodstock, since
that was more or less the first concert of it's size, and that was
during the transition from tube to semi-conductors, and I know that
semi-con... power amps back in those days were prone to failure.

There seems to be a lot of historical information about Woodstock and
other major concerts back in the 60's and 70's, but finding details
such as the type of power amps used to supply the main system just is
not documented.

Mark



People get so caught up in watts these days, there's a lot more to audio
than watts. Large concerts use(d) stacks of amplifiers to achieve the total
power, you need a lot of power coupled to high efficiency speakers to fill
an auditorium or outdoor area with high volume sound, but in your house? How
much space do you have? I have an amp that produces a solid 120W RMS per
channel connected to a pair of moderate efficiency speakers and it's capable
of far higher volume than I would ever wish to listen to. You can get
speakers that will produce enough sound to damage your hearing at 50W, or
you can get them that will require 500W to produce the same volume, look at
those first.

100W is very large for a tube amp, 1KW is outlandish. If you still wish to
proceed, you're asking the wrong group.

wrote in message
...

I want to build a tube power amp for my stereo. Tubes have always had
the best sound.

No, they haven't. A crappy tube system sounds as bad as a crappy solid state
system.

wrote:
On Sat, 12 May 2007 18:37:05 GMT, "James Sweet"
wrote:


wrote in message
...

I want to build a tube power amp for my stereo. Tubes have always had
the best sound. Actually two amps, one for each channel. First off,
what tubes can I use in Push-Pull Parallel to achieve at least 1000
watts RMS per channel. I want real power. Not peak to peak, but true
RMS. Secondly, where can I obtain the output transformers, or will I
have to have them custom made, and where?

When I was much younger I had two amps that used 4 6L6 tubes in
push-pull parallel and I was able to achieve about 120 watts per
channel. The sound was great, but 6L6 tubes have their limits on
power, and tend to be noisy (at least the old ones did, as I had to
shock mount the amps to prevent feedback thru the tubes.

Going with 1000 watts, I will need much more control and tubes that
can handle the abuse. In reality, I'd like to go for 2500 or even
5000 watts per channel, but I doubt any tubes can handle that.

On the other hand. the thought arises to build 4 of these amps, use
two for the low end, and the other two for the horns. I assume that
for the horns I could cut back some on the power output, but need
everything I can get for the bass end, since I intend to build a wall
of 16 inch woofers.

Thanks for all help.

Mark

Is this a joke? 1KW from a tube amp? What do you plan on using for output
transformers? Hope you have a forklift to move them around and a very large
electrical service to power it all. It would eliminate the need for central
heating in your house as well.



No, not a joke. I have wanted all my life to build a stereo that
handles the same power levels as a live concert. I'm now retired and
want to finally do it. Back when I was in my 20's I built my rather
crude system which consisted of 3 separate amplifiers, each putting
out 120Watts RMS, with 4 6L6 tubes in PPP. (The 3rd amp was a
"center" or combined channel that drove a bank of woofers). My huge
speaker towers that I built with one inch thick plywood, held guitar
amp speakers and horns. The power was amazing, but not quite as clean
as I wanted it, and that feedback thru the tubes was always a problem.
Once, when I was rather messed up (I'll skip the details), I cranked
it wide open and blew all the windows out of my apartment (the
landlord was NOT pleased). I attribute the window shattering to low
end distortion, (in a much too small apartment).

Now, I live on a farm and I want to fill the whole farm with
"live-like" sound. I guess you could call it my personal "Woodstock"
(ya, I'm showing my age). Actually handling hundred (or more) pound
transformers/amps would not be a problem, since I actually DO have
tractors and such to move them. but getting the xformers probably is.
I have 400AMP service at my panel, so I got enough power too.

However, I will consider using solid state amps if I can achieve the
right sound. I would imagine I could get some ready made PA system
amps. I used to know a guy that worked for a sound company that did
all the sound for major rock concerts. I know for fact that they had
the capability to run 10,000 watts total, and in most places used the
full amount at outdoor concerts. So, myself wanting to run at least
2000watts total is not too much to ask.

I'm curious why you think this is a joke? I'm asking because there
was a time when everything was tube. What did they use back then for
large concerts and auditoriums for the main system? Ya, I know that
the concerts back in those days were not as large as they have been
since the late 60's. I'm curious what they used at Woodstock, since
that was more or less the first concert of it's size, and that was
during the transition from tube to semi-conductors, and I know that
semi-con... power amps back in those days were prone to failure.

There seems to be a lot of historical information about Woodstock and
other major concerts back in the 60's and 70's, but finding details
such as the type of power amps used to supply the main system just is
not documented.

Mark


I suggest that you first go to a transformer manufacturer and get quotes
on the output trans.

A better idea is to build an amp. for each speaker.

Bill K7NOM

wrote:

I want to build a tube power amp for my stereo. Tubes have always had
the best sound.

Utter nonsense. First off you're got that sodding great lump of steel in the
output transfomer which corrupts everything.

Lateral Mosfets are the best by far.

Graham

"Dave Plowman (News)" wrote:

wrote:

Going with 1000 watts, I will need much more control and tubes that
can handle the abuse. In reality, I'd like to go for 2500 or even
5000 watts per channel, but I doubt any tubes can handle that.

The main interest in valves these days is with SET (single ended
transformer) designs which are the best for that 'valve sound'.

You mean the ones with the highest distortion !

Graham

wrote:

I would imagine I could get some ready made PA system
amps.

Yes. You can get SR (sound re-inforcement as it tends to be called these days
rather than PA) amps with power rating up to about 10kW in a single unit these
days.
http://qscaudio.com/products/amps/po...owerlight3.htm

They aren't designed to be ultra-hi-fi though. Their specs are good but the main
criteria for SR use is power and light weight.

You can however get very good studio monitor type amps of the 1kW / channel
rating.

Graham

Homer J Simpson wrote:

wrote in message

I want to build a tube power amp for my stereo. Tubes have always had
the best sound.

No, they haven't. A crappy tube system sounds as bad as a crappy solid state
system.

Worse usually in fact.

Graham

In article ,
Eeyore wrote:
The main interest in valves these days is with SET (single ended
transformer) designs which are the best for that 'valve sound'.

You mean the ones with the highest distortion !

That and poor damping factor.

--
*A backward poet writes inverse.*

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote:

Eeyore wrote:

The main interest in valves these days is with SET (single ended
transformer) designs which are the best for that 'valve sound'.

You mean the ones with the highest distortion !

That and poor damping factor.

That give that 'better' sound - LOL !

Graham

Dear Mark,

This topic comes up every so often. Today the cost is so prohibitive.
Can you spend $20.00 per watt for parts? If not, better try solid
state. Tubes are simply not available on demand and you will pay
market price for what you can find. Assuming you can spend the money,
take a serious look at the OTL designs of Futterman. They scale well
and do not require an output transformer. Consider wiring your
speakers in series or use custom voice coils so the load is 16 ohms or
more. Eliminate all passive crossovers. Consider multiple amplifiers
per frequency range. Reconsider the choice of speakers. Set an SPL
goal-not a watts goal and work backwards.

VTL labs made a 500 watt tube amp based on 6550s. The Mac MC3500 did
500 watts midband on 6LF6s. You could strap 2 for a 1000 watt single
channel.

On the solid state front, a strapped Bryston 4b sounds fine. BGW has
several offerings. Often, using solid state below 1khz and tube above
is a better answer. There are real issues with power handling at high
frequencies. Few drivers can take the power. Still fewer are worth
listening to. If you use multiple drivers, just use multiple amps.
There are real issues associated with the design of wideband, high
power output transformers. 35 watts is relatively easy. At 60 watts
it is difficult. Above 200 watts becomes rocket science.

Tom

On May 11, 11:04 pm, wrote:
I want to build a tube power amp for my stereo. Tubes have always had
the best sound. Actually two amps, one for each channel. First off,
what tubes can I use in Push-Pull Parallel to achieve at least 1000
watts RMS per channel. I want real power. Not peak to peak, but true
RMS. Secondly, where can I obtain the output transformers, or will I
have to have them custom made, and where?

When I was much younger I had two amps that used 4 6L6 tubes in
push-pull parallel and I was able to achieve about 120 watts per
channel. The sound was great, but 6L6 tubes have their limits on
power, and tend to be noisy (at least the old ones did, as I had to
shock mount the amps to prevent feedback thru the tubes.

Going with 1000 watts, I will need much more control and tubes that
can handle the abuse. In reality, I'd like to go for 2500 or even
5000 watts per channel, but I doubt any tubes can handle that.

On the other hand. the thought arises to build 4 of these amps, use
two for the low end, and the other two for the horns. I assume that
for the horns I could cut back some on the power output, but need
everything I can get for the bass end, since I intend to build a wall
of 16 inch woofers.

Thanks for all help.

Mark

In article . com,
TMI wrote:
Assuming you can spend the money,
take a serious look at the OTL designs of Futterman. They scale well
and do not require an output transformer. Consider wiring your
speakers in series or use custom voice coils so the load is 16 ohms or
more. Eliminate all passive crossovers. Consider multiple amplifiers
per frequency range. Reconsider the choice of speakers. Set an SPL
goal-not a watts goal and work backwards.

The reason to use valves is to get that valve 'sound'. Eliminating some of
the causes of the distortions so beloved of valve enthusiasts defeats the
purpose.

--
*Marriage changes passion - suddenly you're in bed with a relative*

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in
:

In article . com,
TMI wrote:
Assuming you can spend the money,
take a serious look at the OTL designs of Futterman. They scale well
and do not require an output transformer. Consider wiring your
speakers in series or use custom voice coils so the load is 16 ohms or
more. Eliminate all passive crossovers. Consider multiple amplifiers
per frequency range. Reconsider the choice of speakers. Set an SPL
goal-not a watts goal and work backwards.

The reason to use valves is to get that valve 'sound'. Eliminating some
of the causes of the distortions so beloved of valve enthusiasts defeats
the purpose.

Once you have a good amp, without distortion, it is relatively easy to
modify the signal at a low level, to produce any kind of distortion you
might want.

Analogue to Digital(A-D) -- computer -- D-A -- AMP would allow you to
produce a signal with almost any imaginable and certainly any 'real amp'
characteristics that one might desire.



--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

remove ch100-5 to avoid spam trap

In article 39,
bz wrote:
The reason to use valves is to get that valve 'sound'. Eliminating some
of the causes of the distortions so beloved of valve enthusiasts defeats
the purpose.

Once you have a good amp, without distortion, it is relatively easy to
modify the signal at a low level, to produce any kind of distortion you
might want.

Analogue to Digital(A-D) -- computer -- D-A -- AMP would allow you to
produce a signal with almost any imaginable and certainly any 'real amp'
characteristics that one might desire.

You'd need to package it inside some large heavy box that glowed in the
dark, though. Don't underestimate the power of the eyes over the ears.

--
*Why is the word abbreviation so long?

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...

The reason to use valves is to get that valve 'sound'. Eliminating some of
the causes of the distortions so beloved of valve enthusiasts defeats the
purpose.

http://www.computerpoweruser.com/edi...8c09.asp&guid=