[Phil]

Sander deWaal wrote:
Phil said:


Well Andre, it looks like it's you and me, since everyone else has
either pussied out on me (Phil Asshole, Graham), dealt with other
issues, although probably honestly (Scott), or is waiting for further
developments (Patrick). I went by the UT library today, and looked
through several years of JAES, 1980 onward, but only found one article
by Matti Otala. I think maybe he published some papers in IEEE, I'll
have to check. However, in the Jan. 1980 JAES issue, there is an article
by Vanderkooy and Lip****z called "Feedforward Error Correction in Power
Amplifiers" that looks *very* interesting! I haven't thoroughly looked
at it yet, but they review all the various types of feedforward schemes,
starting with the one invented by Harold Black in 1923! They also review
the Quad 405, which is a different type of feedforward, which I can
state from personal experience sounds pretty bad compared to any decent
tube amp.



That you didn't find much after 1980, is because mr. Otala published
his findings in the early '70s.

At that time, the problems as described by him, were a reality in may
commercial amplifiers, and we've learned a lot since then.

Later, people like Daugherty and Greiner proved that (large factors
of) feedback isn't the evil that may seem to think it is, and that it
doesn't necessarily generate additional distortion, when applied
correctly.

I happen to think that Otala has played a major role in getting more
insight in what happens in an amplifier stage with feedback.

Others after him corrected and modified his findings.


There are more ways that lead to Rome.


BTW a modified 405-II can sound very good, at least to these ears.

The Quad I heard was not modified, so I couldn't say, although the one I
heard sounded very good unless compared to a good PP tube amp.

I want to emphasize that the original subject here is not what Phil
Allison implies, namely TIM or SID, but rather the question of whether
negative feedback causes audible problems even when there is no TIM.
I'll go ahead and quote the review of Otala's paper I gave in the other
thread, from "The Audio Critic," Vol 2, #2, p 37, regarding Matti
Otala's analysis of feedback (made after he, the editor Peter Aczel,
Mitch Cotter, Stew Hegeman, Andy Rappaport, Max Wilcox, and Bruce Zayde
had a "BS" session in TAC);

"The paper presents rigorous mathematical proof, for the most
generalized, all-inclusive case, that feedback cannot make amplifier
distortions go away; all it can do is to change one kind of distortion
into another. By the application of feedback, the amplitude
nonlinearities of the open loop are converted into phase nonlinearities
of the closed loop. That's all. The garbage cannot, by definition, be
made to disappear; it's simply swept into another corner. In the typical
feedback amplifier, the amplitude of the audio signal phase-modulates
the high-frequency components of the signal. Furthermore, any amplitude
intermodulation distortion in the open loop is converted into phase
intermodulation distortion in the closed loop. What about TIM, alias
SID? It turns out that it (he?) is a limit case of this
feedback-generated phase modulation effect, with all shades of gray
possible before the actual black eruption occurs. None of this shows up
on standard tests."

I still can't find this paper, despite several trips to the UT library,
but a little thought shows that it actually is consistent with much of
what you and the others ae saying. When an amp with, say, 40 dB of
feedback is hit with a step, the output initially has an "error" of 100
x, *independent* of any gain or load non-linearities, which must be
"corrected" by the feedback loop. For every single change in the input
voltage, the gain is off by a factor of 95 to 105, depending on gain and
load non-linearities, and this error must be corrected by the feedback
loop. Intuitively, it seems obvious that Otala's proof must in *some*
way be correct, that this constant "correction" must play havoc with low
level and high frequency signals. I don't think anyone would deny that,
given an amp with variable feedback followed by a pot to equalize the
overall gain, turning up the feedback will eventually make an amp that,
like the Crown preamp, will "bite your ears off," even if the amp never
gets into TIM territory or other obvious problems. The question is how
much of an effect does Otala's "dynamic phase shifting" have. Here
again, it seems obvious that part of the problem was the S-L-O-W power
transistors of the late '70's, when Otala's various articles were
written. I suspect that high speed devices reduce the problems created
by feedback, the amount of phase distortion produced, and of course
Otala himself came up with several ideas to reduce these effects in his
Citation XX design, although I also haven't been able to find any
literature on that design.

Nevertheless, it is a given, in my mind, that a very high open loop
gain, with its need to constantly "correct" every input signal by 99%
(in the case of 40 dB feedback), *regardless* of the inherent linearity
of the amp's devices and circuit, MUST cause problems for signals 60 dB
to 80 dB below the main signal, and perhaps also phase shift the high
frequency components, as Aczel's summary of Otala's paper states,
thereby robbing the circuit of much of its "life" and "air," the
criticisms one normally hears about high feedback amps, and also solid
state amps, in which the solid state capacitances and high thermal
variations also interfere with low level signals. This will not show up
as TIM or SID, unless the amp has been very poorly designed, and I'm
still not sure how one would measure it. My best guess has been to use a
20 Hz signal and a much smaller (-60 to -80 dB) 10 KHz signal, filter
out the 20 Hz signal from the output with a notch filter plus high pass
filter, and either look directly at the 10 KHz signal for signs of
distress, or filter it out with another notch filter, and see if phase
shifting causes "sidebands" to appear and disappear when the 20 Hz
signal is put in and out of the test.

Assuming that normal feedback causes problems -- and as Patrick says,
with low feedback and tubes it isn't too bad, but SS amps have more
problems and generally need more feedback -- it would be nice if we
could figure out a way to tremendously reduce the need for feedback to
"correct" every normal signal by 99% even when there is no device
distortion, meaning allow the feedback to "focus" *only* on actual
device and load non-linearities. Here is where Black's "feedforward"
circuit may allow for a real advance in SS amps, especially if tubes,
with their (generally) superior ability to handle a mix of high and low
level signals without messing up the low level information, are used to
provide the error signal. Properly applied, Black's feedforward scheme
(but not the feedforward designs by many others!) does exactly this, it
allows feedback to appear and affect the signal *only* when actual
deviations caused by device or load non-linearities appear. It may even
be possible to correct the effects of a typical transistor's parallel
capacitances -- which, being made of silicon, are of *very* poor quality
-- and thermal variations! Normally, this would be a "why waste the
time, just use tubes," situation, but good output transformers are
heavy, big, and expensive, and if the amps used in compact disk players,
as well as TV's, could be considerably improved, that would be nice! And
of course, inexpensive amps that sound very good are always in demand.

Phil

[Eeyore]

Phil wrote:

Sander deWaal wrote:
Phil said:


Well Andre, it looks like it's you and me, since everyone else has
either pussied out on me (Phil Asshole, Graham), dealt with other
issues, although probably honestly (Scott), or is waiting for further
developments (Patrick). I went by the UT library today, and looked
through several years of JAES, 1980 onward, but only found one article
by Matti Otala. I think maybe he published some papers in IEEE, I'll
have to check. However, in the Jan. 1980 JAES issue, there is an article
by Vanderkooy and Lip****z called "Feedforward Error Correction in Power
Amplifiers" that looks *very* interesting! I haven't thoroughly looked
at it yet, but they review all the various types of feedforward schemes,
starting with the one invented by Harold Black in 1923! They also review
the Quad 405, which is a different type of feedforward, which I can
state from personal experience sounds pretty bad compared to any decent
tube amp.



That you didn't find much after 1980, is because mr. Otala published
his findings in the early '70s.

At that time, the problems as described by him, were a reality in may
commercial amplifiers, and we've learned a lot since then.

Later, people like Daugherty and Greiner proved that (large factors
of) feedback isn't the evil that may seem to think it is, and that it
doesn't necessarily generate additional distortion, when applied
correctly.

I happen to think that Otala has played a major role in getting more
insight in what happens in an amplifier stage with feedback.

Others after him corrected and modified his findings.


There are more ways that lead to Rome.


BTW a modified 405-II can sound very good, at least to these ears.

The Quad I heard was not modified, so I couldn't say, although the one I
heard sounded very good unless compared to a good PP tube amp.

I want to emphasize that the original subject here is not what Phil
Allison implies, namely TIM or SID, but rather the question of whether
negative feedback causes audible problems even when there is no TIM.
I'll go ahead and quote the review of Otala's paper I gave in the other
thread, from "The Audio Critic," Vol 2, #2, p 37, regarding Matti
Otala's analysis of feedback (made after he, the editor Peter Aczel,
Mitch Cotter, Stew Hegeman, Andy Rappaport, Max Wilcox, and Bruce Zayde
had a "BS" session in TAC);

"The paper presents rigorous mathematical proof, for the most
generalized, all-inclusive case, that feedback cannot make amplifier
distortions go away; all it can do is to change one kind of distortion
into another. By the application of feedback, the amplitude
nonlinearities of the open loop are converted into phase nonlinearities
of the closed loop. That's all. The garbage cannot, by definition, be
made to disappear; it's simply swept into another corner. In the typical
feedback amplifier, the amplitude of the audio signal phase-modulates
the high-frequency components of the signal. Furthermore, any amplitude
intermodulation distortion in the open loop is converted into phase
intermodulation distortion in the closed loop. What about TIM, alias
SID? It turns out that it (he?) is a limit case of this
feedback-generated phase modulation effect, with all shades of gray
possible before the actual black eruption occurs. None of this shows up
on standard tests."

I still can't find this paper, despite several trips to the UT library,
but a little thought shows that it actually is consistent with much of
what you and the others ae saying. When an amp with, say, 40 dB of
feedback is hit with a step, the output initially has an "error" of 100
x, *independent* of any gain or load non-linearities, which must be
"corrected" by the feedback loop. For every single change in the input
voltage, the gain is off by a factor of 95 to 105, depending on gain and
load non-linearities, and this error must be corrected by the feedback
loop. Intuitively, it seems obvious that Otala's proof must in *some*
way be correct, that this constant "correction" must play havoc with low
level and high frequency signals. I don't think anyone would deny that,
given an amp with variable feedback followed by a pot to equalize the
overall gain, turning up the feedback will eventually make an amp that,
like the Crown preamp, will "bite your ears off," even if the amp never
gets into TIM territory or other obvious problems. The question is how
much of an effect does Otala's "dynamic phase shifting" have. Here
again, it seems obvious that part of the problem was the S-L-O-W power
transistors of the late '70's, when Otala's various articles were
written. I suspect that high speed devices reduce the problems created
by feedback, the amount of phase distortion produced, and of course
Otala himself came up with several ideas to reduce these effects in his
Citation XX design, although I also haven't been able to find any
literature on that design.

Nevertheless, it is a given, in my mind, that a very high open loop
gain, with its need to constantly "correct" every input signal by 99%
(in the case of 40 dB feedback), *regardless* of the inherent linearity
of the amp's devices and circuit, MUST cause problems for signals 60 dB
to 80 dB below the main signal, and perhaps also phase shift the high
frequency components, as Aczel's summary of Otala's paper states,
thereby robbing the circuit of much of its "life" and "air," the
criticisms one normally hears about high feedback amps, and also solid
state amps, in which the solid state capacitances and high thermal
variations also interfere with low level signals. This will not show up
as TIM or SID, unless the amp has been very poorly designed, and I'm
still not sure how one would measure it. My best guess has been to use a
20 Hz signal and a much smaller (-60 to -80 dB) 10 KHz signal, filter
out the 20 Hz signal from the output with a notch filter plus high pass
filter, and either look directly at the 10 KHz signal for signs of
distress, or filter it out with another notch filter, and see if phase
shifting causes "sidebands" to appear and disappear when the 20 Hz
signal is put in and out of the test.

Assuming that normal feedback causes problems -- and as Patrick says,
with low feedback and tubes it isn't too bad, but SS amps have more
problems and generally need more feedback -- it would be nice if we
could figure out a way to tremendously reduce the need for feedback to
"correct" every normal signal by 99% even when there is no device
distortion, meaning allow the feedback to "focus" *only* on actual
device and load non-linearities. Here is where Black's "feedforward"
circuit may allow for a real advance in SS amps, especially if tubes,
with their (generally) superior ability to handle a mix of high and low
level signals without messing up the low level information, are used to
provide the error signal. Properly applied, Black's feedforward scheme
(but not the feedforward designs by many others!) does exactly this, it
allows feedback to appear and affect the signal *only* when actual
deviations caused by device or load non-linearities appear. It may even
be possible to correct the effects of a typical transistor's parallel
capacitances -- which, being made of silicon, are of *very* poor quality
-- and thermal variations! Normally, this would be a "why waste the
time, just use tubes," situation, but good output transformers are
heavy, big, and expensive, and if the amps used in compact disk players,
as well as TV's, could be considerably improved, that would be nice! And
of course, inexpensive amps that sound very good are always in demand.

You do talk a shocking amount of drivel !

Graham

[Arny Krueger]

"Eeyore"
wrote
in message
Phil wrote:

Sander deWaal wrote:
Phil said:


Well Andre, it looks like it's you and me, since
everyone else has either pussied out on me (Phil
Asshole, Graham), dealt with other issues, although
probably honestly (Scott), or is waiting for further
developments (Patrick). I went by the UT library
today, and looked through several years of JAES, 1980
onward, but only found one article by Matti Otala. I
think maybe he published some papers in IEEE, I'll
have to check. However, in the Jan. 1980 JAES issue,
there is an article by Vanderkooy and Lip****z called
"Feedforward Error Correction in Power Amplifiers"
that looks *very* interesting! I haven't thoroughly
looked at it yet, but they review all the various
types of feedforward schemes, starting with the one
invented by Harold Black in 1923! They also review the
Quad 405, which is a different type of feedforward,
which I can state from personal experience sounds
pretty bad compared to any decent tube amp.



That you didn't find much after 1980, is because mr.
Otala published his findings in the early '70s.

At that time, the problems as described by him, were a
reality in may commercial amplifiers, and we've learned
a lot since then.

Later, people like Daugherty and Greiner proved that
(large factors of) feedback isn't the evil that may
seem to think it is, and that it doesn't necessarily
generate additional distortion, when applied correctly.

I happen to think that Otala has played a major role in
getting more insight in what happens in an amplifier
stage with feedback.

Others after him corrected and modified his findings.


There are more ways that lead to Rome.


BTW a modified 405-II can sound very good, at least to
these ears.

The Quad I heard was not modified, so I couldn't say,
although the one I heard sounded very good unless
compared to a good PP tube amp.

I want to emphasize that the original subject here is
not what Phil Allison implies, namely TIM or SID, but
rather the question of whether negative feedback causes
audible problems even when there is no TIM. I'll go
ahead and quote the review of Otala's paper I gave in
the other thread, from "The Audio Critic," Vol 2, #2, p
37, regarding Matti Otala's analysis of feedback (made
after he, the editor Peter Aczel, Mitch Cotter, Stew
Hegeman, Andy Rappaport, Max Wilcox, and Bruce Zayde had
a "BS" session in TAC);

"The paper presents rigorous mathematical proof, for the
most generalized, all-inclusive case, that feedback
cannot make amplifier distortions go away; all it can do
is to change one kind of distortion into another. By the
application of feedback, the amplitude nonlinearities of
the open loop are converted into phase nonlinearities of
the closed loop. That's all. The garbage cannot, by
definition, be made to disappear; it's simply swept into
another corner. In the typical feedback amplifier, the
amplitude of the audio signal phase-modulates the
high-frequency components of the signal. Furthermore,
any amplitude intermodulation distortion in the open
loop is converted into phase intermodulation distortion
in the closed loop. What about TIM, alias SID? It turns
out that it (he?) is a limit case of this
feedback-generated phase modulation effect, with all
shades of gray possible before the actual black eruption
occurs. None of this shows up on standard tests."

I still can't find this paper, despite several trips to
the UT library, but a little thought shows that it
actually is consistent with much of what you and the
others ae saying. When an amp with, say, 40 dB of
feedback is hit with a step, the output initially has an
"error" of 100 x, *independent* of any gain or load
non-linearities, which must be "corrected" by the
feedback loop. For every single change in the input
voltage, the gain is off by a factor of 95 to 105,
depending on gain and load non-linearities, and this
error must be corrected by the feedback loop.
Intuitively, it seems obvious that Otala's proof must in
*some* way be correct, that this constant "correction"
must play havoc with low level and high frequency
signals. I don't think anyone would deny that, given an
amp with variable feedback followed by a pot to equalize
the overall gain, turning up the feedback will
eventually make an amp that, like the Crown preamp, will
"bite your ears off," even if the amp never gets into
TIM territory or other obvious problems. The question is
how much of an effect does Otala's "dynamic phase
shifting" have. Here again, it seems obvious that part
of the problem was the S-L-O-W power transistors of the
late '70's, when Otala's various articles were written.
I suspect that high speed devices reduce the problems
created by feedback, the amount of phase distortion
produced, and of course Otala himself came up with
several ideas to reduce these effects in his Citation XX
design, although I also haven't been able to find any
literature on that design.

Nevertheless, it is a given, in my mind, that a very
high open loop gain, with its need to constantly
"correct" every input signal by 99% (in the case of 40
dB feedback), *regardless* of the inherent linearity of
the amp's devices and circuit, MUST cause problems for
signals 60 dB to 80 dB below the main signal, and
perhaps also phase shift the high frequency components,
as Aczel's summary of Otala's paper states, thereby
robbing the circuit of much of its "life" and "air," the
criticisms one normally hears about high feedback amps,
and also solid state amps, in which the solid state
capacitances and high thermal variations also interfere
with low level signals. This will not show up as TIM or
SID, unless the amp has been very poorly designed, and
I'm still not sure how one would measure it. My best
guess has been to use a 20 Hz signal and a much smaller
(-60 to -80 dB) 10 KHz signal, filter out the 20 Hz
signal from the output with a notch filter plus high
pass filter, and either look directly at the 10 KHz
signal for signs of distress, or filter it out with
another notch filter, and see if phase shifting causes
"sidebands" to appear and disappear when the 20 Hz
signal is put in and out of the test.

Assuming that normal feedback causes problems -- and as
Patrick says, with low feedback and tubes it isn't too
bad, but SS amps have more problems and generally need
more feedback -- it would be nice if we could figure out
a way to tremendously reduce the need for feedback to
"correct" every normal signal by 99% even when there is
no device distortion, meaning allow the feedback to
"focus" *only* on actual device and load
non-linearities. Here is where Black's "feedforward"
circuit may allow for a real advance in SS amps,
especially if tubes, with their (generally) superior
ability to handle a mix of high and low level signals
without messing up the low level information, are used
to provide the error signal. Properly applied, Black's
feedforward scheme (but not the feedforward designs by
many others!) does exactly this, it allows feedback to
appear and affect the signal *only* when actual
deviations caused by device or load non-linearities
appear. It may even be possible to correct the effects
of a typical transistor's parallel capacitances --
which, being made of silicon, are of *very* poor quality
-- and thermal variations! Normally, this would be a
"why waste the time, just use tubes," situation, but
good output transformers are heavy, big, and expensive,
and if the amps used in compact disk players, as well as
TV's, could be considerably improved, that would be
nice! And of course, inexpensive amps that sound very
good are always in demand.

You do talk a shocking amount of drivel !

I think "Phil" is just Moncreiff or Jung posting under an alias. ;-)

[Phil]

Eeyore wrote:

Phil wrote:


Sander deWaal wrote:

Phil said:



Well Andre, it looks like it's you and me, since everyone else has
either pussied out on me (Phil Asshole, Graham), dealt with other
issues, although probably honestly (Scott), or is waiting for further
developments (Patrick). I went by the UT library today, and looked
through several years of JAES, 1980 onward, but only found one article
by Matti Otala. I think maybe he published some papers in IEEE, I'll
have to check. However, in the Jan. 1980 JAES issue, there is an article
by Vanderkooy and Lip****z called "Feedforward Error Correction in Power
Amplifiers" that looks *very* interesting! I haven't thoroughly looked
at it yet, but they review all the various types of feedforward schemes,
starting with the one invented by Harold Black in 1923! They also review
the Quad 405, which is a different type of feedforward, which I can
state from personal experience sounds pretty bad compared to any decent
tube amp.



That you didn't find much after 1980, is because mr. Otala published
his findings in the early '70s.

At that time, the problems as described by him, were a reality in may
commercial amplifiers, and we've learned a lot since then.

Later, people like Daugherty and Greiner proved that (large factors
of) feedback isn't the evil that may seem to think it is, and that it
doesn't necessarily generate additional distortion, when applied
correctly.

I happen to think that Otala has played a major role in getting more
insight in what happens in an amplifier stage with feedback.

Others after him corrected and modified his findings.


There are more ways that lead to Rome.


BTW a modified 405-II can sound very good, at least to these ears.


The Quad I heard was not modified, so I couldn't say, although the one I
heard sounded very good unless compared to a good PP tube amp.

I want to emphasize that the original subject here is not what Phil
Allison implies, namely TIM or SID, but rather the question of whether
negative feedback causes audible problems even when there is no TIM.
I'll go ahead and quote the review of Otala's paper I gave in the other
thread, from "The Audio Critic," Vol 2, #2, p 37, regarding Matti
Otala's analysis of feedback (made after he, the editor Peter Aczel,
Mitch Cotter, Stew Hegeman, Andy Rappaport, Max Wilcox, and Bruce Zayde
had a "BS" session in TAC);

"The paper presents rigorous mathematical proof, for the most
generalized, all-inclusive case, that feedback cannot make amplifier
distortions go away; all it can do is to change one kind of distortion
into another. By the application of feedback, the amplitude
nonlinearities of the open loop are converted into phase nonlinearities
of the closed loop. That's all. The garbage cannot, by definition, be
made to disappear; it's simply swept into another corner. In the typical
feedback amplifier, the amplitude of the audio signal phase-modulates
the high-frequency components of the signal. Furthermore, any amplitude
intermodulation distortion in the open loop is converted into phase
intermodulation distortion in the closed loop. What about TIM, alias
SID? It turns out that it (he?) is a limit case of this
feedback-generated phase modulation effect, with all shades of gray
possible before the actual black eruption occurs. None of this shows up
on standard tests."

I still can't find this paper, despite several trips to the UT library,
but a little thought shows that it actually is consistent with much of
what you and the others ae saying. When an amp with, say, 40 dB of
feedback is hit with a step, the output initially has an "error" of 100
x, *independent* of any gain or load non-linearities, which must be
"corrected" by the feedback loop. For every single change in the input
voltage, the gain is off by a factor of 95 to 105, depending on gain and
load non-linearities, and this error must be corrected by the feedback
loop. Intuitively, it seems obvious that Otala's proof must in *some*
way be correct, that this constant "correction" must play havoc with low
level and high frequency signals. I don't think anyone would deny that,
given an amp with variable feedback followed by a pot to equalize the
overall gain, turning up the feedback will eventually make an amp that,
like the Crown preamp, will "bite your ears off," even if the amp never
gets into TIM territory or other obvious problems. The question is how
much of an effect does Otala's "dynamic phase shifting" have. Here
again, it seems obvious that part of the problem was the S-L-O-W power
transistors of the late '70's, when Otala's various articles were
written. I suspect that high speed devices reduce the problems created
by feedback, the amount of phase distortion produced, and of course
Otala himself came up with several ideas to reduce these effects in his
Citation XX design, although I also haven't been able to find any
literature on that design.

Nevertheless, it is a given, in my mind, that a very high open loop
gain, with its need to constantly "correct" every input signal by 99%
(in the case of 40 dB feedback), *regardless* of the inherent linearity
of the amp's devices and circuit, MUST cause problems for signals 60 dB
to 80 dB below the main signal, and perhaps also phase shift the high
frequency components, as Aczel's summary of Otala's paper states,
thereby robbing the circuit of much of its "life" and "air," the
criticisms one normally hears about high feedback amps, and also solid
state amps, in which the solid state capacitances and high thermal
variations also interfere with low level signals. This will not show up
as TIM or SID, unless the amp has been very poorly designed, and I'm
still not sure how one would measure it. My best guess has been to use a
20 Hz signal and a much smaller (-60 to -80 dB) 10 KHz signal, filter
out the 20 Hz signal from the output with a notch filter plus high pass
filter, and either look directly at the 10 KHz signal for signs of
distress, or filter it out with another notch filter, and see if phase
shifting causes "sidebands" to appear and disappear when the 20 Hz
signal is put in and out of the test.

Assuming that normal feedback causes problems -- and as Patrick says,
with low feedback and tubes it isn't too bad, but SS amps have more
problems and generally need more feedback -- it would be nice if we
could figure out a way to tremendously reduce the need for feedback to
"correct" every normal signal by 99% even when there is no device
distortion, meaning allow the feedback to "focus" *only* on actual
device and load non-linearities. Here is where Black's "feedforward"
circuit may allow for a real advance in SS amps, especially if tubes,
with their (generally) superior ability to handle a mix of high and low
level signals without messing up the low level information, are used to
provide the error signal. Properly applied, Black's feedforward scheme
(but not the feedforward designs by many others!) does exactly this, it
allows feedback to appear and affect the signal *only* when actual
deviations caused by device or load non-linearities appear. It may even
be possible to correct the effects of a typical transistor's parallel
capacitances -- which, being made of silicon, are of *very* poor quality
-- and thermal variations! Normally, this would be a "why waste the
time, just use tubes," situation, but good output transformers are
heavy, big, and expensive, and if the amps used in compact disk players,
as well as TV's, could be considerably improved, that would be nice! And
of course, inexpensive amps that sound very good are always in demand.


You do talk a shocking amount of drivel !

Graham

Here's a suggestion, Useless: Why don't you share with us some of YOUR
insights and analyses so we could what "non-drivel" looks like. Unless,
of course, a useless pussy like yourself (or Arny) has none, or is too
much of a coward to stick your neck out. The only useless drivel I see
is the CONSTANT use by you and Arny of that same old, OLD, tired,
debating trick of putting out a general criticism, with no specific
examples, and no supporting evidence. And no matter how many times it
gets pointed out to you, we can all count on one thing; your next post
will do it again. I've seen useless pussies before, but until you two
came along, I had not seen petrified useless pussies. You two are
unique, that I'll admit.

Phil

[Eeyore]

Phil wrote:

Eeyore wrote:
Phil wrote:
It may even
be possible to correct the effects of a typical transistor's parallel
capacitances -- which, being made of silicon, are of *very* poor quality
-- and thermal variations!

Bwahahahahahhaha !

Normally, this would be a "why waste the
time, just use tubes," situation, but good output transformers are
heavy, big, and expensive, and if the amps used in compact disk players,
as well as TV's, could be considerably improved, that would be nice! And
of course, inexpensive amps that sound very good are always in demand.


You do talk a shocking amount of drivel !

Graham

Here's a suggestion, Useless: Why don't you share with us some of YOUR
insights and analyses so we could what "non-drivel" looks like.

Well........ since it would be based on sound engineering science, I suspect it
might have limited appeal.


Unless,
of course, a useless pussy like yourself (or Arny) has none, or is too
much of a coward to stick your neck out. The only useless drivel I see
is the CONSTANT use by you and Arny of that same old, OLD, tired,
debating trick of putting out a general criticism, with no specific
examples, and no supporting evidence. And no matter how many times it
gets pointed out to you, we can all count on one thing; your next post
will do it again. I've seen useless pussies before, but until you two
came along, I had not seen petrified useless pussies. You two are
unique, that I'll admit.

If you knew anything about electronic design and solid-state physics you
wouldn't make such stupid comments about parallel capacitance in transistors for
example.

Tell me more about this and how it works and them I'll correct you OK ?

Graham

[Phil]

Eeyore wrote:

Phil wrote:


Eeyore wrote:

Phil wrote:

It may even

be possible to correct the effects of a typical transistor's parallel
capacitances -- which, being made of silicon, are of *very* poor quality
-- and thermal variations!


Bwahahahahahhaha !


Normally, this would be a "why waste the

time, just use tubes," situation, but good output transformers are
heavy, big, and expensive, and if the amps used in compact disk players,
as well as TV's, could be considerably improved, that would be nice! And
of course, inexpensive amps that sound very good are always in demand.


You do talk a shocking amount of drivel !

Graham


Here's a suggestion, Useless: Why don't you share with us some of YOUR
insights and analyses so we could what "non-drivel" looks like.


Well........ since it would be based on sound engineering science, I suspect it
might have limited appeal.



Unless,
of course, a useless pussy like yourself (or Arny) has none, or is too
much of a coward to stick your neck out. The only useless drivel I see
is the CONSTANT use by you and Arny of that same old, OLD, tired,
debating trick of putting out a general criticism, with no specific
examples, and no supporting evidence. And no matter how many times it
gets pointed out to you, we can all count on one thing; your next post
will do it again. I've seen useless pussies before, but until you two
came along, I had not seen petrified useless pussies. You two are
unique, that I'll admit.


If you knew anything about electronic design and solid-state physics you
wouldn't make such stupid comments about parallel capacitance in transistors for
example.

Tell me more about this and how it works and them I'll correct you OK ?

Graham

Sure. You know the gate to source, gate to drain, and the drain to
source capacitances? In a solid state transistor, they are made out of a
dielectric called "silicon" -- not coincidentally, the same thing the
FETS are made of -- and it has a dielectric constant of 12, quite high.
Good, low dielectric constant materials, with constants of 2 to 3, have
enough dielectric absorption to require precision instruments to use
several parallel RC units to offset the noise dumped by the main
capacitors (see p 220 of Horowitz and Hill, "The Art of Electronics").
High dielectric materials are much worse (note the usual warnings for
electrolytic caps, with a mere dielectric constant of 7 to 8), and
NOBODY in their right mind would even dream of using a silicon capacitor
in any circuit required to pass signals in which many important signals
are 80 dB or more below the main signals; you know, like you find in music?

Take just the Cds cap: as the signal moves up and down, the dielectric
absorption of this cap stores and releases energy all the time,
polluting the signal. This pollution is at a very low level, and if
music only used about 40 dB or so, it *might* not be noticeable, or at
least, just barely noticeable. But with music the range is closer to 100
dB, even with analog (humans can easily hear 40 dB into noise, something
the old telegraph operators normally achieved). In contrast, a vacuum
tube has capacitances made out of, well, a vacuum, the medium of space,
which has, as far as we know, no dielectric absorption at all. In
addition -- as you, of course, already know, as can be proven in some of
your old posts here -- the transistor's capacitances *vary* as a
function of both voltage and heat, and the heat varies as a function of
the device's recent signal history, meaning it does *not* follow the
musical signal in a harmonic way, but rather as an rms average over the
most recent second or so. When a capacitance increases or decreases, and
the voltage remains the same, guess what? That's right, the charge
increases or decreases, meaning it gets sucked from or dumped into the
signal in a non-harmonic way. Now, if we have a device with vacuum
capacitors to compare the input versus the silicon capacitor gunked-up
output, we might, just might, be able to offset the crap dumped into the
signal by those capacitors. Clear enough?

Now, you can go into debate mode, in which truth, honesty, and
intelligence are meaningless, and the only goal is to attack your
"opponent's" statements, or you can be honest here. Gee, what do I think
a useless pussy like you will do? Golly, that's a hard one ... Let's
see, "Well, see, modern transistors are free of this." Excuse me, have
you LOOKED at the cap data for MOSFETS (or even power bipolars) lately?
For very small signals, using very small transistors, you can reduce
this effect to -60 dB or so, with great care maybe even -80 dB, or with
tremendous care and many offsetting components, maybe 120 dB, which I
suspect would then be inaudible. But I do not know of a preamp design
which achieves anywhere near 120 dB, although I obviously have not seen
all the circuits out there. Wake up, useless; I will unhappily admit
that I am all too frequently wrong, but I am NOT stupid, and only a
useless, sanctimonious snot like yourself would even try to convince
himself otherwise. But maybe I'm just kidding myself, because maybe you
can list some of your old posts here that not only discuss the subject
of the effect that the solid state parasitic capacitances have on audio
circuits, but which are free of the "many errors" that you will claim
exist, but as always, without actually giving even one example of these
errors. Oh, and no word -- of course -- concerning how many of my points
are correct; that would violate debate rules, which are the only rules
that anyone should ever use! You know, I have terminal cancer, and maybe
heart problems (waiting for the results), but I would rather be me, and
dead soon, than an utterly useless pussy like you, for decades. And no,
my physical problems should NEVER excuse me from INTELLIGENT criticism.

Disgusted Phil

[Phil Allison]

"Phil"


You know, I have terminal cancer, and maybe heart problems (waiting for
the results),


** Don't be so modest with your medical boasting -

you also have terminal autism and bi-polar disorder.



but I would rather be me, and dead soon,


** Then we all have something to look forward to.





........ Phil

[Phil]

Phil Allison wrote:
"Phil"


You know, I have terminal cancer, and maybe heart problems (waiting for
the results),



** Don't be so modest with your medical boasting -

you also have terminal autism and bi-polar disorder.




but I would rather be me, and dead soon,



** Then we all have something to look forward to.





....... Phil



Now THIS is cute!

Impressed Phil

[paul packer]

On Sat, 9 Sep 2006 15:02:13 +1000, "Phil Allison"
wrote:


"Phil"


You know, I have terminal cancer, and maybe heart problems (waiting for
the results),


** Don't be so modest with your medical boasting -

you also have terminal autism and bi-polar disorder.



but I would rather be me, and dead soon,


** Then we all have something to look forward to.





....... Phil


You have a heart as big as all outdoors, Phil.

[Arny Krueger]

"Phil" wrote in message


Nevertheless, it is a given, in my mind, that a very high
open loop gain, with its need to constantly "correct"
every input signal by 99% (in the case of 40 dB
feedback), *regardless* of the inherent linearity of the
amp's devices and circuit, MUST cause problems for
signals 60 dB to 80 dB below the main signal, and perhaps
also phase shift the high frequency components, as
Aczel's summary of Otala's paper states, thereby robbing
the circuit of much of its "life" and "air," the
criticisms one normally hears about high feedback amps,
and also solid state amps, in which the solid state
capacitances and high thermal variations also interfere
with low level signals.

Could you be more presumptious or wrong, Phil?

This will not show up as TIM or
SID, unless the amp has been very poorly designed, and
I'm still not sure how one would measure it.

There's really no way to measure your imagination, Phil.


My best
guess has been to use a 20 Hz signal and a much smaller
(-60 to -80 dB) 10 KHz signal, filter out the 20 Hz
signal from the output with a notch filter plus high pass
filter, and either look directly at the 10 KHz signal for
signs of distress, or filter it out with another notch
filter, and see if phase shifting causes "sidebands" to
appear and disappear when the 20 Hz signal is put in and
out of the test.

You're looking for the unholy Grail, Phil.

People don't use notch filters that much any more. They just apply the test
signal and analyze the amp's output with a very good spectrum analyzer.


Assuming that normal feedback causes problems

That takes a lot of ignorance or paranoia.

-- and as
Patrick says, with low feedback and tubes it isn't too
bad, but SS amps have more problems and generally need
more feedback

SS amps don't have more problems, if well-designed.

-- it would be nice if we could figure out
a way to tremendously reduce the need for feedback to
"correct" every normal signal by 99% even when there is
no device distortion, meaning allow the feedback to
"focus" *only* on actual device and load non-linearities.

The error here is that there are any unavoidable problems with the
application of lots of feedback.


Here is where Black's "feedforward" circuit may allow for
a real advance in SS amps, especially if tubes, with
their (generally) superior ability to handle a mix of
high and low level signals without messing up the low
level information, are used to provide the error signal.

In fact tubes have no such advantages.

Properly applied, Black's feedforward scheme (but not the
feedforward designs by many others!) does exactly this,
it allows feedback to appear and affect the signal *only*
when actual deviations caused by device or load
non-linearities appear.

This is nuts.

It may even be possible to
correct the effects of a typical transistor's parallel
capacitances -- which, being made of silicon, are of
*very* poor quality -- and thermal variations!

Making really good power amps with silicon transistors is an old art that is
quite well perfected at this time.

Normally,
this would be a "why waste the time, just use tubes,"
situation, but good output transformers are heavy, big,
and expensive, and if the amps used in compact disk
players, as well as TV's, could be considerably improved,
that would be nice! And of course, inexpensive amps that
sound very good are always in demand.

Thats why so many of them are made and sold - there's lots of demand for
them.

[George M. Middius]

Another dose of Krooglish gets Mr. **** girded for his weekend joust with
Rev. Poop-Head at the Goose Puke Baptist church.

Could you be more presumptious

Nobody in the history of the world has ever been "presumptious", you dumb
****. Stop lying, please.




--

"Christians have to ... work to make the world as loving, just, and supportive as is possible."
A. Krooger, Aug. 2006

[Arny Krueger]

"George M. Middius" cmndr [underscore] george [at] comcast
[dot] net wrote in message

Another dose of Krooglish gets Mr. **** girded for his
weekend joust with Rev. Poop-Head at the Goose Puke
Baptist church.

Could you be more presumptious

Nobody in the history of the world has ever been
"presumptious", you dumb ****. Stop lying, please.

Note Middius' amazing ability to herniate in public himself over a typo.

[George M. Middius]

More lies from LiarBorg. I'm not surprised. Shall we notify Rev. Poop-Head
that Arnii is renewing his vows to be a good "chrisitan"? ;-)

Could you be more presumptious

Nobody in the history of the world has ever been
"presumptious", you dumb ****. Stop lying, please.

Note Middius' amazing ability to herniate[sic] in public himself over a typo.

"I apologize for being presumptious."
A. Krooger, 20 July 2000

"Since I'm not claiming to be able to read your mind, the act you consider
presumptious did not happen."
A. Krooger, 17 June 2000

"Presumptious little minx aren't you, Jenn?"
A. Krooger, 4 April 2006

"... any reasonable male would be a lot more worried about the
"Presumptious" part."
A. Krooger, 7 September 2001




--

"Christians have to ... work to make the world as loving, just, and supportive as is possible."
A. Krooger, Aug. 2006

[Jenn]

In article ,
George M. Middius cmndr [underscore] george [at] comcast [dot] net
wrote:

More lies from LiarBorg. I'm not surprised. Shall we notify Rev. Poop-Head
that Arnii is renewing his vows to be a good "chrisitan"? ;-)

Could you be more presumptious

Nobody in the history of the world has ever been
"presumptious", you dumb ****. Stop lying, please.

Note Middius' amazing ability to herniate[sic] in public himself over a
typo.

"I apologize for being presumptious."
A. Krooger, 20 July 2000

"Since I'm not claiming to be able to read your mind, the act you consider
presumptious did not happen."
A. Krooger, 17 June 2000

"Presumptious little minx aren't you, Jenn?"
A. Krooger, 4 April 2006

I'd forgotten about that post LOL


"... any reasonable male would be a lot more worried about the
"Presumptious" part."
A. Krooger, 7 September 2001




--

"Christians have to ... work to make the world as loving, just, and
supportive as is possible."
A. Krooger, Aug. 2006

[Eeyore]

"George M. Middius" wrote:

More lies from LiarBorg. I'm not surprised. Shall we notify Rev. Poop-Head
that Arnii is renewing his vows to be a good "chrisitan"? ;-)

Could you be more presumptious

Nobody in the history of the world has ever been
"presumptious", you dumb ****. Stop lying, please.

Note Middius' amazing ability to herniate[sic] in public himself over a typo.

"I apologize for being presumptious."
A. Krooger, 20 July 2000

"Since I'm not claiming to be able to read your mind, the act you consider
presumptious did not happen."
A. Krooger, 17 June 2000

"Presumptious little minx aren't you, Jenn?"
A. Krooger, 4 April 2006

"... any reasonable male would be a lot more worried about the
"Presumptious" part."
A. Krooger, 7 September 2001

How's that new sub-editor position going btw Georgie Porgy puddikins ?

Graham

[Eeyore]

"George M. Middius" wrote:

Another dose of Krooglish gets Mr. **** girded for his weekend joust with
Rev. Poop-Head at the Goose Puke Baptist church.

Could you be more presumptious

Nobody in the history of the world has ever been "presumptious", you dumb
****. Stop lying, please.

Ejsy fof upi dsu ?

Graham

[Robert Morein]

"George M. Middius" wrote:
Another dose of Krooglish gets Mr. **** girded for his weekend joust with
Rev. Poop-Head at the Goose Puke Baptist church.

Could you be more presumptious

Nobody in the history of the world has ever been "presumptious", you dumb
****. Stop lying, please.


"I'd like to have as many men and women as possible **** me in the ass
before I die"
George Middius, 8th Grade Graduation Ceremony