A tube amp enthusiast pal of mine has asked
if there is any way he can "record" his tube
power amp via a sound card, for comparison
with my amp. Using a microphone,
however good, in front of a speaker, does not
seem to be a good way to go about this.

We have totally different speakers, and different
listening environments, plus the fact that we
live 300 kms apart.

Can the signal from the OPT secondary be
attenuated and matched to feed a sound card
across a dummy load? Or how can it be done?

Any ideas?

Iain

On Fri, 17 Jun 2005 13:15:22 +0300, "Iain M Churches"
wrote:

A tube amp enthusiast pal of mine has asked
if there is any way he can "record" his tube
power amp via a sound card, for comparison
with my amp. Using a microphone,
however good, in front of a speaker, does not
seem to be a good way to go about this.

We have totally different speakers, and different
listening environments, plus the fact that we
live 300 kms apart.

Can the signal from the OPT secondary be
attenuated and matched to feed a sound card
across a dummy load? Or how can it be done?

Any ideas?

Iain



Certainly. Just wire a volume control of perhaps 1k across the speaker
terminals (leave the speaker connected as well), and take the output
from one end of the pot and the slider. Adjust for optimum input level
to the sound card.

d

Pearce Consulting
http://www.pearce.uk.com

"Don Pearce" wrote in message
...
On Fri, 17 Jun 2005 13:15:22 +0300, "Iain M Churches"
wrote:

A tube amp enthusiast pal of mine has asked
if there is any way he can "record" his tube
power amp via a sound card, for comparison
with my amp. Using a microphone,
however good, in front of a speaker, does not
seem to be a good way to go about this.

We have totally different speakers, and different
listening environments, plus the fact that we
live 300 kms apart.

Can the signal from the OPT secondary be
attenuated and matched to feed a sound card
across a dummy load? Or how can it be done?

Any ideas?

Iain



Certainly. Just wire a volume control of perhaps 1k across the speaker
terminals (leave the speaker connected as well), and take the output
from one end of the pot and the slider. Adjust for optimum input level
to the sound card.

d

Doesn't the variation in non linear load which various
speakers present to the amplifier affect the performance?
Would a dummy load be better?

Iain

On Fri, 17 Jun 2005 14:18:36 +0300, "Iain M Churches"
wrote:


"Don Pearce" wrote in message
...
On Fri, 17 Jun 2005 13:15:22 +0300, "Iain M Churches"
wrote:

A tube amp enthusiast pal of mine has asked
if there is any way he can "record" his tube
power amp via a sound card, for comparison
with my amp. Using a microphone,
however good, in front of a speaker, does not
seem to be a good way to go about this.

We have totally different speakers, and different
listening environments, plus the fact that we
live 300 kms apart.

Can the signal from the OPT secondary be
attenuated and matched to feed a sound card
across a dummy load? Or how can it be done?

Any ideas?

Iain



Certainly. Just wire a volume control of perhaps 1k across the speaker
terminals (leave the speaker connected as well), and take the output
from one end of the pot and the slider. Adjust for optimum input level
to the sound card.

d

Doesn't the variation in non linear load which various
speakers present to the amplifier affect the performance?
Would a dummy load be better?

Iain


Yes and no. If you want to know how the amplifier actually sounds, you
need the speaker. If all you want is how it could possibly sound given
a sympathetic load, then the dummy will do.

The degree of difference between the two is a good measure of
competence for the amplifier.

d

Pearce Consulting
http://www.pearce.uk.com

"Don Pearce" wrote in message
...
On Fri, 17 Jun 2005 14:18:36 +0300, "Iain M Churches"
wrote:


"Don Pearce" wrote in message
...
On Fri, 17 Jun 2005 13:15:22 +0300, "Iain M Churches"
wrote:

A tube amp enthusiast pal of mine has asked
if there is any way he can "record" his tube
power amp via a sound card, for comparison
with my amp. Using a microphone,
however good, in front of a speaker, does not
seem to be a good way to go about this.

We have totally different speakers, and different
listening environments, plus the fact that we
live 300 kms apart.

Can the signal from the OPT secondary be
attenuated and matched to feed a sound card
across a dummy load? Or how can it be done?

Any ideas?

Iain



Certainly. Just wire a volume control of perhaps 1k across the speaker
terminals (leave the speaker connected as well), and take the output
from one end of the pot and the slider. Adjust for optimum input level
to the sound card.

d

Doesn't the variation in non linear load which various
speakers present to the amplifier affect the performance?
Would a dummy load be better?

Iain


Yes and no. If you want to know how the amplifier actually sounds, you
need the speaker. If all you want is how it could possibly sound given
a sympathetic load, then the dummy will do.

The degree of difference between the two is a good measure of
competence for the amplifier.

Yes. I see. But comparing two different amplifiers with two different
pairs of loudspeakers is adding another variable to the equation, it
seems to me.

So maybe for comparison sake, a dummy load might
be best. I suppose one could shunt the R with some capacitance to
make it look more like a real world load.

Iain.

On Fri, 17 Jun 2005 14:41:52 +0300, "Iain M Churches"
wrote:


"Don Pearce" wrote in message
...
On Fri, 17 Jun 2005 14:18:36 +0300, "Iain M Churches"
wrote:


"Don Pearce" wrote in message
...
On Fri, 17 Jun 2005 13:15:22 +0300, "Iain M Churches"
wrote:

A tube amp enthusiast pal of mine has asked
if there is any way he can "record" his tube
power amp via a sound card, for comparison
with my amp. Using a microphone,
however good, in front of a speaker, does not
seem to be a good way to go about this.

We have totally different speakers, and different
listening environments, plus the fact that we
live 300 kms apart.

Can the signal from the OPT secondary be
attenuated and matched to feed a sound card
across a dummy load? Or how can it be done?

Any ideas?

Iain



Certainly. Just wire a volume control of perhaps 1k across the speaker
terminals (leave the speaker connected as well), and take the output
from one end of the pot and the slider. Adjust for optimum input level
to the sound card.

d

Doesn't the variation in non linear load which various
speakers present to the amplifier affect the performance?
Would a dummy load be better?

Iain


Yes and no. If you want to know how the amplifier actually sounds, you
need the speaker. If all you want is how it could possibly sound given
a sympathetic load, then the dummy will do.

The degree of difference between the two is a good measure of
competence for the amplifier.

Yes. I see. But comparing two different amplifiers with two different
pairs of loudspeakers is adding another variable to the equation, it
seems to me.

So maybe for comparison sake, a dummy load might
be best. I suppose one could shunt the R with some capacitance to
make it look more like a real world load.

Iain.


The big variation is really the huge impedance lump (or lumps for a
reflex) around resonance. You could agree between you on a dummy load
with some appropriate reactances. There must be a standard one
somewhere.

d

Pearce Consulting
http://www.pearce.uk.com

"Iain M Churches" wrote in message
...
A tube amp enthusiast pal of mine has asked
if there is any way he can "record" his tube
power amp via a sound card, for comparison
with my amp. Using a microphone,
however good, in front of a speaker, does not
seem to be a good way to go about this.

We have totally different speakers, and different
listening environments, plus the fact that we
live 300 kms apart.

Can the signal from the OPT secondary be
attenuated and matched to feed a sound card
across a dummy load? Or how can it be done?

Any ideas?

Iain

Just out of curiosity, if you DO record the output, how is he going to
listen to it without going through yet another amp and another pair of
speakers? What will your comparison then be worth?


???

BFoelsch wrote:
"Iain M Churches" wrote in message
...
A tube amp enthusiast pal of mine has asked
if there is any way he can "record" his tube
power amp via a sound card, for comparison
with my amp. Using a microphone,
however good, in front of a speaker, does not
seem to be a good way to go about this.

We have totally different speakers, and different
listening environments, plus the fact that we
live 300 kms apart.

Can the signal from the OPT secondary be
attenuated and matched to feed a sound card
across a dummy load? Or how can it be done?

Any ideas?

Iain

Just out of curiosity, if you DO record the output, how is he going to
listen to it without going through yet another amp and another pair of
speakers? What will your comparison then be worth?


???
A guy over on alt.guitar.amps put it well when he wrote that audio speakers REproduce sound, whereas guitar speakers PRODUCE sound. You put a Shure SM-57 or the equivalent next to a speaker. There's no other rational way.

--Bryan

Iain M Churches wrote:

A tube amp enthusiast pal of mine has asked
if there is any way he can "record" his tube
power amp via a sound card, for comparison
with my amp. Using a microphone,
however good, in front of a speaker, does not
seem to be a good way to go about this.

We have totally different speakers, and different
listening environments, plus the fact that we
live 300 kms apart.

Can the signal from the OPT secondary be
attenuated and matched to feed a sound card
across a dummy load? Or how can it be done?

Any ideas?

Iain



The proper question here is what are you hoping to accomplish with this
exercise??

Is it that you have not heard a tube amp yourself?? Or?

Then a reasonable answer may or may not be available.

_-_-bear

Doesn't the variation in non linear load which various
speakers present to the amplifier affect the performance?
Would a dummy load be better?


You could create a dummy load that more closely
simulates the inductances and resistances of
a real speaker. There's a few "standard" speaker
simulation loads floating around, ONe is to use
a 6.8 ohm resistor in series with a 1mH coil, and
that is series with the following parts in parallel:
500uF non polar cap, 22 ohm resistor and 20mH coil.
Your friend could build the same dummy load, and
record his amp as well, then play both recordings
thru his system to listen for differences.

There is really no way to record the amp and have an accurate depiction
of what it actually sounds like. Even if you could, we must not forget
just how crappy the typical computer 'sound' card is.

If you want to compare the amps, the ONLY WAY, is to connect them in an
A/B configuration("A/B'ing" both the inputs as well as the outputs),
using the same preamp and/or program input, the same speakers, in the
same room. Sit back with the a/b control in hand and compare to your
heart's content.

Hope this helps

El Chico Gordo
The Great Randi of Audio

Iain M Churches wrote:
A tube amp enthusiast pal of mine has asked
if there is any way he can "record" his tube
power amp via a sound card, for comparison
with my amp. Using a microphone,
however good, in front of a speaker, does not
seem to be a good way to go about this.

We have totally different speakers, and different
listening environments, plus the fact that we
live 300 kms apart.

Can the signal from the OPT secondary be
attenuated and matched to feed a sound card
across a dummy load? Or how can it be done?

Any ideas?

Iain

On 18 Jun 2005 19:07:12 -0700, wrote:

There is really no way to record the amp and have an accurate depiction
of what it actually sounds like. Even if you could, we must not forget
just how crappy the typical computer 'sound' card is.

If you want to compare the amps, the ONLY WAY, is to connect them in an
A/B configuration("A/B'ing" both the inputs as well as the outputs),
using the same preamp and/or program input, the same speakers, in the
same room. Sit back with the a/b control in hand and compare to your
heart's content.

Hope this helps

It probably would if it had either been right or made any sense.

First up - even the cheapest and nastiest computer sound cards
available these days are vastly better than any tube amp, and yes,
what you record this way is a very accurate representation of what the
tube amp is delivering to the speakers.

And having a pair of recorded files, you are then in a position to
analyse them any way you like. You can do it technically with DAW
software to establish frequency response, compression or whatever. Or
you can play them back through another power amp and speakers to
assess them audibly. Of course, for this playback you should use a
solid state amp so there will be no further degeneration of the
signal, and you can properly assess the effects of the tubes.

As to what that sounds like, of course - that depends on the speakers.
But the fact that the question even needs posing speaks volumes for
the fact that such an amp is likely to interact adversely with speaker
impedances to produce a non-optimal sound output.

And of course, what he is seeking is some sensible way to compare two
amps that are physically separated by a great distance - so
pontificating on the *only* way to do the job being to have them in
the same room is about as much use as a chocolate teapot.

In what way did you imagine that any of it might have helped?

d

Pearce Consulting
http://www.pearce.uk.com

Don Pearce wrote:

On 18 Jun 2005 19:07:12 -0700, wrote:


There is really no way to record the amp and have an accurate depiction
of what it actually sounds like. Even if you could, we must not forget
just how crappy the typical computer 'sound' card is.

If you want to compare the amps, the ONLY WAY, is to connect them in an
A/B configuration("A/B'ing" both the inputs as well as the outputs),
using the same preamp and/or program input, the same speakers, in the
same room. Sit back with the a/b control in hand and compare to your
heart's content.

Hope this helps


It probably would if it had either been right or made any sense.

First up - even the cheapest and nastiest computer sound cards
available these days are vastly better than any tube amp, and yes,
what you record this way is a very accurate representation of what the
tube amp is delivering to the speakers.

And having a pair of recorded files, you are then in a position to
analyse them any way you like. You can do it technically with DAW
software to establish frequency response, compression or whatever. Or
you can play them back through another power amp and speakers to
assess them audibly. Of course, for this playback you should use a
solid state amp so there will be no further degeneration of the
signal, and you can properly assess the effects of the tubes.

As to what that sounds like, of course - that depends on the speakers.
But the fact that the question even needs posing speaks volumes for
the fact that such an amp is likely to interact adversely with speaker
impedances to produce a non-optimal sound output.

And of course, what he is seeking is some sensible way to compare two
amps that are physically separated by a great distance - so
pontificating on the *only* way to do the job being to have them in
the same room is about as much use as a chocolate teapot.

In what way did you imagine that any of it might have helped?

d

Pearce Consulting
http://www.pearce.uk.com

The sound card may or may not be good technically - but then again any
run-of-the mill CD player has vanishingly low distortion when measured,
but if you think they all sound the same, or they all sound "good" then
that pretty much defines your perceptions and beliefs in a nutshell.

So, what do these "sound card specs" tell us about how things will sound
coming off ur computer? Not much.

I agree however that it should be *possible* for a sound card to
*possibly* show someone how a given tube amp "sounds" in some instances.
But it is far from a certainty.

Would that be a reasonable or "valid" comparison upon which to base a
judgement on the subjective qualities of the recorded amp? Probably not,
and at best entirely unclear.

Why? because artifacts that are present & added by the playback system
will alter the perception of the orginal amp's recording - *assuming in
the first place* that the recording did not add any audible artifacts.

And, if you think there are no "added artifacts" to be added by a given
system or recording process, I would posit that this is a nice fantasy.

Anyhow, the recording idea is perhaps worth trying, but I would draw no
conclusions from such a "test."

_-_-bear

On Sun, 19 Jun 2005 13:26:52 -0400, BEAR wrote:

The sound card may or may not be good technically - but then again any
run-of-the mill CD player has vanishingly low distortion when measured,
but if you think they all sound the same, or they all sound "good" then
that pretty much defines your perceptions and beliefs in a nutshell.

So, what do these "sound card specs" tell us about how things will sound
coming off ur computer? Not much.

I agree however that it should be *possible* for a sound card to
*possibly* show someone how a given tube amp "sounds" in some instances.
But it is far from a certainty.

Would that be a reasonable or "valid" comparison upon which to base a
judgement on the subjective qualities of the recorded amp? Probably not,
and at best entirely unclear.

Why? because artifacts that are present & added by the playback system
will alter the perception of the orginal amp's recording - *assuming in
the first place* that the recording did not add any audible artifacts.

And, if you think there are no "added artifacts" to be added by a given
system or recording process, I would posit that this is a nice fantasy.

Anyhow, the recording idea is perhaps worth trying, but I would draw no
conclusions from such a "test."

_-_-bear

This is a vacuous argument. The artifacts present on even an average
sound card are vanishingly small compared to those of a valve amp. The
comparison is perfectly valid.

d

Pearce Consulting
http://www.pearce.uk.com

FWIW we've been up against the same basic challenge on the other side
of the street (music creation vs reproduction) for years. I'd stop at
the thought of "sound card" & use a good external A/D interface
(Tascam, etc.) before going any further, as cards themselves vary all
over the place whereas most A/D units of reasonable quality are pretty
uniform & do a much better job. Perhaps with this & Robert's suggested
dummy providing more uniformity, you'd have signals with a reasonably
close standard of comparability. You could both add the same and
simple line out ckt (just a small pad) to feed it, too. Perhaps you
both could subjectively eval the results using the same set (or at
least model) of headphones (also using the A/D interface & not sound
cards)for economy & more uniformity. Most interfaces also have a
high-quality built-in headphone monitor out (yes it is SS). Perhaps
you could borrow one or send one back/forth. Another thing you could
additionally do this way is use the same CD, then sync both the results
& the CD track in common audio editing s/w to accurately visually
compare them, if of value.

If neither of you owns a good A/D, it'd probably be cheaper & more
accurate to drive both ways with your spkrs & be done with it, with
only your different rooms impacting any results. That depends on the
costs of any other hospitality mutually extended. ;-)

We have totally different speakers, and different
listening environments, plus the fact that we
live 300 kms apart.


Another thing to remember: DO NOT compress the files.
That would introduce another set of artifacts that
will just confuse the comparisons.

I can say from experience that it can not be done. First, speaker loads
present differently to different amps. There is NO way to accurately
record the audio signal form the output of an amplifier. With that
said, different listening environments sound completely different.

So unless both amplifiers are A/B'ed with identical sources, with the
same speakers and speaker positioning, in an identical listening
environment, it's hard to compare the two.

But that's not the main problem OP faces. The main problem is that it's
impossible to accurately record the amplifiers.

Between the really crappy audio chain and cheap D/A-A/D conversion
stages, 95 percent(probably more) of the computer "sound" cards sound
absolutely hideous. If you believe that even the crappiest of computer
sound cards sound acceptable, you, my friend, need to seriously
consider a different career.

Here's a hint, Don - Listen with your ears, and NOT with your eyes.
What looks good on an analyzer, does not mean it's going to sound good
to the ears.

El Chico Gordo
The Great Randi of audio

Don Pearce wrote:


This is a vacuous argument. The artifacts present on even an average
sound card are vanishingly small compared to those of a valve amp. The
comparison is perfectly valid.

d

Pearce Consulting
http://www.pearce.uk.com

On Sun, 19 Jun 2005 17:43:19 GMT, (Don Pearce)
wrote:


This is a vacuous argument. The artifacts present on even an average
sound card are vanishingly small compared to those of a valve amp. The
comparison is perfectly valid.

This is true if you assume monotonicity. Not everyone will
agree with the assumption. (Especially for a sound card; jeez.)

Chris Hornbeck

I can say from experience that it can not be done. First, speaker loads
present differently to different amps. There is NO way to accurately
record the audio signal form the output of an amplifier. With that
said, different listening environments sound completely different.

So unless both amplifiers are A/B'ed with identical sources, with the
same speakers and speaker positioning, in an identical listening
environment, it's hard to compare the two.

But that's not the main problem OP faces. The main problem is that it's
impossible to accurately record the amplifiers.

Between the really crappy audio chain and cheap D/A-A/D conversion
stages, 95 percent(probably more) of the computer "sound" cards sound
absolutely hideous. If you believe that even the crappiest of computer
sound cards sound acceptable, you, my friend, need to seriously
reconsider your career.

Here's a hint, Don - Listen with your ears, and NOT with your eyes.
What looks good on an analyzer, does not mean it's going to sound good
to the ears.

El Chico Gordo
The Great Randi of audio

Don Pearce wrote:
On Sun, 19 Jun 2005 13:26:52 -0400, BEAR wrote:
_-_-bear

This is a vacuous argument. The artifacts present on even an average
sound card are vanishingly small compared to those of a valve amp. The
comparison is perfectly valid.

d

Pearce Consulting
http://www.pearce.uk.com

On 19 Jun 2005 20:33:31 -0700, wrote:

I can say from experience that it can not be done. First, speaker loads
present differently to different amps. There is NO way to accurately
record the audio signal form the output of an amplifier. With that
said, different listening environments sound completely different.

Yes there is. A computer sound card will do nicely. It is several
orders of magnitude more accurate than what you are trying to record,
so it will be fine.

So unless both amplifiers are A/B'ed with identical sources, with the
same speakers and speaker positioning, in an identical listening
environment, it's hard to compare the two.

We've already covered that.

But that's not the main problem OP faces. The main problem is that it's
impossible to accurately record the amplifiers.

No it isn't. It would be difficult to accurately record a decent solid
state amp, but here we are talking about a pair of tube amps that the
poster believes may sound different. That speaks volumes for the
quality (or rather the lack of) of the amplifiers in question. At that
level of badness it is no problem at all to record the deficiencies.

Between the really crappy audio chain and cheap D/A-A/D conversion
stages, 95 percent(probably more) of the computer "sound" cards sound
absolutely hideous. If you believe that even the crappiest of computer
sound cards sound acceptable, you, my friend, need to seriously
reconsider your career.

I was talking about an average sound card, not the crappiest. If you
need to lie in order to win your argument, then just go away. I have
an average sound card - an Echo Mia. Its sound is, as far as I am
concerned, immaculate. I don't take terribly seriously this kind of
talk from somebody who deliberately chooses a distorting medium for
sound reproduction.

Here's a hint, Don - Listen with your ears, and NOT with your eyes.
What looks good on an analyzer, does not mean it's going to sound good
to the ears.

I do use my ears. The average tubie, of course, uses his eyes,
drooling over the glow in the bottle.

El Chico Gordo
The Great Randi of audio


d

Pearce Consulting
http://www.pearce.uk.com

On Mon, 20 Jun 2005 03:10:50 GMT, Chris Hornbeck
wrote:

On Sun, 19 Jun 2005 17:43:19 GMT, (Don Pearce)
wrote:


This is a vacuous argument. The artifacts present on even an average
sound card are vanishingly small compared to those of a valve amp. The
comparison is perfectly valid.

This is true if you assume monotonicity. Not everyone will
agree with the assumption. (Especially for a sound card; jeez.)

Chris Hornbeck

Find me a modern sound card that doesn't have monotonicity. Just
because tube technology development stopped in the 1920s, that doesn't
mean sound card design did.

And of course the number of people who agree is irrelevant. You don't
vote for facts.

d
Pearce Consulting
http://www.pearce.uk.com

"robert casey" wrote in message
ink.net...

Doesn't the variation in non linear load which various
speakers present to the amplifier affect the performance?
Would a dummy load be better?


You could create a dummy load that more closely
simulates the inductances and resistances of
a real speaker. There's a few "standard" speaker
simulation loads floating around, ONe is to use
a 6.8 ohm resistor in series with a 1mH coil, and
that is series with the following parts in parallel:
500uF non polar cap, 22 ohm resistor and 20mH coil.
Your friend could build the same dummy load, and
record his amp as well, then play both recordings
thru his system to listen for differences.

Thanks for that, Robert. Our plan is to record from
the same CD, with the CD player feeding the power
amp direct via a stepped attenuator. Then we thought
to record the output of the amps to a .wav file, which
we can exchange for comparison.

Iain

wrote in message
oups.com...
A guy over on alt.guitar.amps put it well when he wrote that audio
speakers REproduce sound, whereas guitar speakers PRODUCE sound. You put
a Shure SM-57 or the equivalent next to a speaker. There's no other
rational way.


--Bryan


I have tried that with a Neumann 87 (probablya much
better mic than anything Shure can offer) But then
we add more variables to the equation -
the micropone and the room.
We want only one factor as a possible
variable, the amp under evaluation.

Iain

wrote in message
oups.com...
There is really no way to record the amp and have an accurate depiction
of what it actually sounds like. Even if you could, we must not forget
just how crappy the typical computer 'sound' card is.

If you want to compare the amps, the ONLY WAY, is to connect them in an
A/B configuration("A/B'ing" both the inputs as well as the outputs),
using the same preamp and/or program input, the same speakers, in the
same room. Sit back with the a/b control in hand and compare to your
heart's content.

Hope this helps

El Chico Gordo
The Great Randi of Audio

We were hoping that modern technology would supply an
alternative to transporting a 25kg amp with a 50kg
psu a distance of 300km.

Iain

"robert casey" wrote in message
ink.net...


We have totally different speakers, and different
listening environments, plus the fact that we
live 300 kms apart.


Another thing to remember: DO NOT compress the files.
That would introduce another set of artifacts that
will just confuse the comparisons.

OK., We were thinking of nothing less than .wav files


Iain

On Mon, 20 Jun 2005 11:27:40 +0300, "Iain M Churches"
wrote:


wrote in message
roups.com...
There is really no way to record the amp and have an accurate depiction
of what it actually sounds like. Even if you could, we must not forget
just how crappy the typical computer 'sound' card is.

If you want to compare the amps, the ONLY WAY, is to connect them in an
A/B configuration("A/B'ing" both the inputs as well as the outputs),
using the same preamp and/or program input, the same speakers, in the
same room. Sit back with the a/b control in hand and compare to your
heart's content.

Hope this helps

El Chico Gordo
The Great Randi of Audio

We were hoping that modern technology would supply an
alternative to transporting a 25kg amp with a 50kg
psu a distance of 300km.

Iain


Iain, please just ignore all these nay sayers. Your idea for
comparison is a good one, and it will work just fine. Hopefully you
will find that there is no identifiable difference between the
amplifiers which will tell you that they are both good.

Of course, if there is a difference you then have the interesting
problem of working out which is the bad one, and which is the good.

d

Pearce Consulting
http://www.pearce.uk.com

Don Pearce wrote:
Yes there is. A computer sound card will do nicely. It is several
orders of magnitude more accurate than what you are trying to record,
so it will be fine.

Sorry, but 95 percent of computer sound cards sound like ass.


So unless both amplifiers are A/B'ed with identical sources, with the
same speakers and speaker positioning, in an identical listening
environment, it's hard to compare the two.

We've already covered that.

That's the only way to do it. Any other way presents countless
inaccuracies.



But that's not the main problem OP faces. The main problem is that it's
impossible to accurately record the amplifiers.

No it isn't. It would be difficult to accurately record a decent solid
state amp, but here we are talking about a pair of tube amps that the
poster believes may sound different. That speaks volumes for the
quality (or rather the lack of) of the amplifiers in question. At that
level of badness it is no problem at all to record the deficiencies.

In your eyes, why is it difficult to record a solid state amp
accurately, but not a tube amp? Please humor me.




Between the really crappy audio chain and cheap D/A-A/D conversion
stages, 95 percent(probably more) of the computer "sound" cards sound
absolutely hideous. If you believe that even the crappiest of computer
sound cards sound acceptable, you, my friend, need to seriously
reconsider your career.

I was talking about an average sound card, not the crappiest. If you
need to lie in order to win your argument, then just go away. I have
an average sound card - an Echo Mia. Its sound is, as far as I am
concerned, immaculate. I don't take terribly seriously this kind of
talk from somebody who deliberately chooses a distorting medium for
sound reproduction.


The average computer sound card has crappy D/A-A/D conversion, very bad
audio chains, and are voltage starved. Though, there are several cards
out there which give admirable performance at this voltage range. If
you think the average sound card sounds good to you, again, I steer you
to re-examine your career choice.


Here's a hint, Don - Listen with your ears, and NOT with your eyes.
What looks good on an analyzer, does not mean it's going to sound good
to the ears.

I do use my ears. The average tubie, of course, uses his eyes,
drooling over the glow in the bottle.

What ever you say. I think it boils down to one thing here, Don Pearce
think that tubes don't sound as good as solid state devices. In other
words, what Don says here, is gospel. Have I het the nail on the head?


El Chico Gordo
The Great Randi of audio

On Mon, 20 Jun 2005 06:07:34 GMT, (Don Pearce)
wrote:

This is a vacuous argument. The artifacts present on even an average
sound card are vanishingly small compared to those of a valve amp. The
comparison is perfectly valid.

This is true if you assume monotonicity. Not everyone will
agree with the assumption. (Especially for a sound card; jeez.)

Find me a modern sound card that doesn't have monotonicity. Just
because tube technology development stopped in the 1920s, that doesn't
mean sound card design did.

Monotonicity isn't something that you have or not; it's an ideal
that no real world component exhibits.

Many otherwise inexplicably weird modern audio trends are
attempts to deal with monotonicity, whether the builder
understands the issue or not. Sometimes the sacrifices in
other, usually high level, characteristics must seem
very strange to those who, assuming perfect monotonicity,
look at high level behavior and call the job done.

Chris Hornbeck
1700? Impeach.

On 20 Jun 2005 15:09:18 -0700, wrote:

Don Pearce wrote:
Yes there is. A computer sound card will do nicely. It is several
orders of magnitude more accurate than what you are trying to record,
so it will be fine.

Sorry, but 95 percent of computer sound cards sound like ass.


No, they don't. You habitually listen to a medium that delights in
distorting the sound - that is why you are in no position to judge the
quality of a high-quality medium.


So unless both amplifiers are A/B'ed with identical sources, with the
same speakers and speaker positioning, in an identical listening
environment, it's hard to compare the two.

We've already covered that.

That's the only way to do it. Any other way presents countless
inaccuracies.

No, they can be counted and quantified. And they are small. Hence it
works.


But that's not the main problem OP faces. The main problem is that it's
impossible to accurately record the amplifiers.

No it isn't. It would be difficult to accurately record a decent solid
state amp, but here we are talking about a pair of tube amps that the
poster believes may sound different. That speaks volumes for the
quality (or rather the lack of) of the amplifiers in question. At that
level of badness it is no problem at all to record the deficiencies.

In your eyes, why is it difficult to record a solid state amp
accurately, but not a tube amp? Please humor me.


What Iain is trying to find is differences - errors if you like. In
tube amps those errors are large - many orders of magnitude larger
than the errors in a sound card. With a solid state amp the errors are
of a similar order to those in a sound card. Hence it is easy to do
this job on a tube amp, but not a solid state one. Humored?




Between the really crappy audio chain and cheap D/A-A/D conversion
stages, 95 percent(probably more) of the computer "sound" cards sound
absolutely hideous. If you believe that even the crappiest of computer
sound cards sound acceptable, you, my friend, need to seriously
reconsider your career.

I was talking about an average sound card, not the crappiest. If you
need to lie in order to win your argument, then just go away. I have
an average sound card - an Echo Mia. Its sound is, as far as I am
concerned, immaculate. I don't take terribly seriously this kind of
talk from somebody who deliberately chooses a distorting medium for
sound reproduction.


The average computer sound card has crappy D/A-A/D conversion, very bad
audio chains, and are voltage starved. Though, there are several cards
out there which give admirable performance at this voltage range. If
you think the average sound card sounds good to you, again, I steer you
to re-examine your career choice.

By your choice of tubes, you are ill-positioned to make such a
judgment. You like the sound of distortion.


Here's a hint, Don - Listen with your ears, and NOT with your eyes.
What looks good on an analyzer, does not mean it's going to sound good
to the ears.

I do use my ears. The average tubie, of course, uses his eyes,
drooling over the glow in the bottle.

What ever you say. I think it boils down to one thing here, Don Pearce
think that tubes don't sound as good as solid state devices. In other
words, what Don says here, is gospel. Have I het the nail on the head?


My opinion is my opinion - as is yours. You are welcome to your
opinion of tube sound, about which I frankly couldn't care less. But
when it comes to accuracy - which is of the essence here - solid state
has them whipped every time. And that isn't opinion - hard facts and
measurements will back this up.

It encourages me somewhat that when you ran out of arguments, you
resorted instead to insults.

d

Pearce Consulting
http://www.pearce.uk.com

On Mon, 20 Jun 2005 22:23:56 GMT, Chris Hornbeck
wrote:

On Mon, 20 Jun 2005 06:07:34 GMT, (Don Pearce)
wrote:

This is a vacuous argument. The artifacts present on even an average
sound card are vanishingly small compared to those of a valve amp. The
comparison is perfectly valid.

This is true if you assume monotonicity. Not everyone will
agree with the assumption. (Especially for a sound card; jeez.)

Find me a modern sound card that doesn't have monotonicity. Just
because tube technology development stopped in the 1920s, that doesn't
mean sound card design did.

Monotonicity isn't something that you have or not; it's an ideal
that no real world component exhibits.


Nonsense. Monotonicity is a standard term in an A/D or D/A spec. I
have dealt with many, and I have never come across one that wasn't
guaranteed monotonic (at least since the early seventies).

Many otherwise inexplicably weird modern audio trends are
attempts to deal with monotonicity, whether the builder
understands the issue or not. Sometimes the sacrifices in
other, usually high level, characteristics must seem
very strange to those who, assuming perfect monotonicity,
look at high level behavior and call the job done.

Have you any idea what meaningless gibberish you have just written?
You aren't religious, by any chance, are you?

d

Pearce Consulting
http://www.pearce.uk.com

On Mon, 20 Jun 2005 22:35:24 GMT, (Don Pearce)
wrote:

Have you any idea what meaningless gibberish you have just written?
You aren't religious, by any chance, are you?

The first-glance obvious interpretation of your response is that
of a closed minded reflexive defense against a novel concept.

That just doesn't sound like you, based on many informative
posts over the years.

Puzzled,

Chris Hornbeck
1700? Impeach.

It encourages me somewhat that when you ran out of arguments, you
resorted instead to insults.

No Don, the problem here is, clearly, your ego. You simply cannot admit
to being incorrect.

I speak from experience. What OP wants to do, simply can not be done
with any semblence of accuracy.
I've tried it. I've tried it. And, I've tride it again. There is really
no way to accurately record the output so as to reproduce it in another
environment.

Your admitance of how good you feel the average computer sound card
sounds, speaks volumes. You clearly don't appear to know what you are
talking about, or, your reproducing equipment is faulty/cheap.

El Chico Gordo

Iain M Churches wrote:

We were hoping that modern technology would supply an
alternative to transporting a 25kg amp with a 50kg
psu a distance of 300km.

You've been given some good suggestions for getting you are close as is
reasonable. But you do not see the humor and inherent conflict in your
own words.

(contextually translated):

"We were hoping that we could ignore the inherent vagarities of
accurately comparing two 90 year old technologies by adding some modern
technology to the mix."

:-)

On Tue, 21 Jun 2005 00:34:13 GMT, Chris Hornbeck
wrote:

On Mon, 20 Jun 2005 22:35:24 GMT, (Don Pearce)
wrote:

Have you any idea what meaningless gibberish you have just written?
You aren't religious, by any chance, are you?

The first-glance obvious interpretation of your response is that
of a closed minded reflexive defense against a novel concept.

That just doesn't sound like you, based on many informative
posts over the years.

Puzzled,

Well, Puzzled. It was actually me defending the novel concept, and
everybody else shouting "No, it won't work".

d

Pearce Consulting
http://www.pearce.uk.com

On 20 Jun 2005 19:00:32 -0700, wrote:

It encourages me somewhat that when you ran out of arguments, you
resorted instead to insults.

No Don, the problem here is, clearly, your ego. You simply cannot admit
to being incorrect.

I speak from experience. What OP wants to do, simply can not be done
with any semblence of accuracy.
I've tried it. I've tried it. And, I've tride it again. There is really
no way to accurately record the output so as to reproduce it in another
environment.

Your admitance of how good you feel the average computer sound card
sounds, speaks volumes. You clearly don't appear to know what you are
talking about, or, your reproducing equipment is faulty/cheap.

El Chico Gordo

If this is what you believe, I wish you well with it.

d

Pearce Consulting
http://www.pearce.uk.com