[[email protected]]

Per request, the lowdown on amp DBTs. We don=92t need a lengthy list this t=
ime, because old RAHE friend Tom Nousaine did us the favor of summarizing t=
hem for an AES conference paper some years ago:

http://www.aes.org/e-lib/browse.cfm?elib=3D5426

From his conclusion:

=93In summary, there has been no evidence to support the conclusion that fa=
ctors other than linear response and output capability contribute to the so=
und of well designed power amplifiers...

=93This does not suggest that amplifiers are perfect and they will never be=
found to sound different. It does suggest to purchasers of today's audio a=
mplifiers that as long as the product in question meets basic traditional m=
easured performance standards, has enough output capability, and adequate q=
uality of construction, it will be sonically indistinguishable from all oth=
ers meeting those criteria.=94

Once again, Brian Moore=92s textbook, An Introduction to the Psychology of =
Hearing, concurs:

=93The basic performance of even a moderately priced hi-fi amplifier is lik=
ely to be so good that improvements in technical specification would make l=
ittle audible difference. For example, a moderately good amplifier will hav=
e a frequency response from 20 to 20,000 Hz +/=96 1 dB, distortion less tha=
n 1% and a signal-to-noise ratio greater than 90 dB (for input signals with=
a reasonably high level, such as from a CD player). These values are bette=
r than the limits required by the ear.=94

And just for fun, here=92s a DBT from the Matrix HiFi guys that involves mo=
re than just amplifiers, this time in handy English:

http://www.matrixhifi.com/ENG_marco.htm

(Click on Blind Tests, and then on the subsequent link.)

Perhaps the inferior high-end cables masked the superiority of the high-end=
amplification?

Once again, no empirically plausible evidence has ever been presented on th=
e other side.

bob

[Audio_Empire[_2_]]

On Wednesday, December 12, 2012 5:28:11 PM UTC-8, wrote:
Per request, the lowdown on amp DBTs. We don=92t need a lengthy list this=
time, because old RAHE friend Tom Nousaine did us the favor of summarizing=
them for an AES conference paper some years ago:
=20
=20
=20
http://www.aes.org/e-lib/browse.cfm?elib=3D5426
=20
=20
=20
From his conclusion:
=20
=20
=20
=93In summary, there has been no evidence to support the conclusion that =
factors other than linear response and output capability contribute to the =
sound of well designed power amplifiers...
=20
=20
=20
=93This does not suggest that amplifiers are perfect and they will never =
be found to sound different. It does suggest to purchasers of today's audio=
amplifiers that as long as the product in question meets basic traditional=
measured performance standards, has enough output capability, and adequate=
quality of construction, it will be sonically indistinguishable from all o=
thers meeting those criteria.=94
=20
=20
=20
Once again, Brian Moore=92s textbook, An Introduction to the Psychology o=
f Hearing, concurs:
=20
=20
=20
=93The basic performance of even a moderately priced hi-fi amplifier is l=
ikely to be so good that improvements in technical specification would make=
little audible difference. For example, a moderately good amplifier will h=
ave a frequency response from 20 to 20,000 Hz +/=96 1 dB, distortion less t=
han 1% and a signal-to-noise ratio greater than 90 dB (for input signals wi=
th a reasonably high level, such as from a CD player). These values are bet=
ter than the limits required by the ear.=94
=20
=20
=20
And just for fun, here=92s a DBT from the Matrix HiFi guys that involves =
more than just amplifiers, this time in handy English:
=20
=20
=20
http://www.matrixhifi.com/ENG_marco.htm
=20
=20
=20
(Click on Blind Tests, and then on the subsequent link.)
=20
=20
=20
Perhaps the inferior high-end cables masked the superiority of the high-e=
nd amplification?
=20
=20
=20
Once again, no empirically plausible evidence has ever been presented on =
the other side.
=20
=20
=20
bob

"This does not suggest that amplifiers are perfect and they will never=20
be found to sound different." The sound of an amplifier is directly=20
proportional to the extent of the differences found between them
and how far each differs from theoretical perfection.

For instance. Lets take two modern, solid-state amplifiers. Let us
stipulate that both are fairly equal in power output, distortion and
frequency response. But, let's say that one of the amps has an average
run-of-the-mill power supply while the other has a huge supply with
separate and very large power transformers and separate
supplies for each channel capable of sourcing many more amps of
current to the second amp than is available to the first. Now. lets=20
operate both amps near their limits with difficult loads. I'll guarantee=20
you that even though they might measure almost identically in the=20
above mentioned parameters, under normal circumstances, in these=20
circumstances, the amp with the largest supply is going to sound better.

[[email protected]]

On Thursday, December 13, 2012 6:42:06 AM UTC-5, Audio_Empire wrote:

For instance. Lets take two modern, solid-state amplifiers. Let us
stipulate that both are fairly equal in power output, distortion and
frequency response. But, let's say that one of the amps has an average
run-of-the-mill power supply while the other has a huge supply with
separate and very large power transformers and separate
supplies for each channel capable of sourcing many more amps of
current to the second amp than is available to the first. Now. lets
operate both amps near their limits with difficult loads. I'll guarantee
you that even though they might measure almost identically in the
above mentioned parameters, under normal circumstances, in these
circumstances, the amp with the largest supply is going to sound better.

In that case, they won't really be "fairly equal in power output." There will be substantial measured differences, most evident in the power-vs-distortion curves.

[Arny Krueger[_5_]]

"Audio_Empire" wrote in message
...

"This does not suggest that amplifiers are perfect and they will never
be found to sound different." The sound of an amplifier is directly
proportional to the extent of the differences found between them
and how far each differs from theoretical perfection.

Actually, there is no such global proportionality. There is a point where
audible differences become small enough that they are not discerned by the
human ear, and are simply not noticed no matter how ideal the circumstances.

For instance. Lets take two modern, solid-state amplifiers. Let us
stipulate that both are fairly equal in power output, distortion and
frequency response.

Which would seem to falsify the following:

But, let's say that one of the amps has an average
run-of-the-mill power supply while the other has a huge supply with
separate and very large power transformers and separate
supplies for each channel capable of sourcing many more amps of
current to the second amp than is available to the first.

As long as the power supply of an amplifier is adequate to maintain internal
voltages within the realm of sufficiency, any excess capability has no
effect on either measured performance or sound quality.

It's just excess weight and expense.


Now. lets operate both amps near their limits with difficult loads.

The above statement continues to hold: As long as the power supply of an
amplifier is adequate to maintain internal voltages within the realm of
sufficiency, any excess capability has no effect on either measured
performance or sound quality.


I'll guarantee you that even though they might measure almost identically
in the
above mentioned parameters, under normal circumstances, in these
circumstances, the amp with the largest supply is going to sound better.

Your guarantee is worthless because it violates both actual experience and
the principles of physics.

[Audio_Empire[_2_]]

On Thursday, December 13, 2012 2:44:59 PM UTC-8, Arny Krueger wrote:
"Audio_Empire" wrote in message

...



"This does not suggest that amplifiers are perfect and they will never

be found to sound different." The sound of an amplifier is directly

proportional to the extent of the differences found between them

and how far each differs from theoretical perfection.



Actually, there is no such global proportionality. There is a point where

audible differences become small enough that they are not discerned by the

human ear, and are simply not noticed no matter how ideal the circumstances.


I disagree and we've had this discussion before. I do agree that under
normal listening conditions, the sonic differences between modern
solid-state amps are tiny and mostly inconsequential, In a DBT or ABX
test, a person might actually slightly prefer one amp over the other,
but if that person were to take one of those amps home, he would not
remember what those differences were after about an hour of listening.
They are that small and that unimportant, but they do exist. Of
course, these comments apply only to solid-state amps, Tubes are a
different kettle of fish altogether. The sky's the limit for their
aberrations, but some people like tubes. I had a pair VTL 140 mono
blocks for years, and I liked the colorations. Still do. But, my new
amp is solid-state and I like the transparency that it affords as
well. BTW, I have Behringer A500 (I believe that you said you have one
too). and I find that it's very transparent (if you keep the level
controls on the front panel at maximum). The fact that someone can
sell an amp that clean, powerful, and built that sturdily for around
$200 (street) tells me that almost everybody in the consumer
marketplace are ripping their customers off (the Behringer is supposed
to be a sound reinforcement or recording monitor amp, not a consumer
product)!



For instance. Lets take two modern, solid-state amplifiers. Let us

stipulate that both are fairly equal in power output, distortion and

frequency response.



Which would seem to falsify the following:

Yes, and in what way? These amps are spec'd similarly
and if both are measured one channel at a time (like
the manufacturer obviously did when he spec'd the smaller
single-supply amp) They will continue to measure similarly.


But, let's say that one of the amps has an average

run-of-the-mill power supply while the other has a huge supply with

separate and very large power transformers and separate

supplies for each channel capable of sourcing many more amps of

current to the second amp than is available to the first.



As long as the power supply of an amplifier is adequate to maintain internal

voltages within the realm of sufficiency, any excess capability has no

effect on either measured performance or sound quality.



It's just excess weight and expense.





Now. lets operate both amps near their limits with difficult loads.



The above statement continues to hold: As long as the power supply of an

amplifier is adequate to maintain internal voltages within the realm of

sufficiency, any excess capability has no effect on either measured

performance or sound quality.

But That's the point, isn't it? In the case of two, say, 150
Watt/channel amps. The one with the single supply might be able to
maintain that output with ONE channel driven, but not both. Of course
the published specs won't say that, and more importantly, if the amp
is measured one channel at a time, the measurements won't show that
either.


I'll guarantee you that even though they might measure almost identically

in the

above mentioned parameters, under normal circumstances, in these

circumstances, the amp with the largest supply is going to sound better.



Your guarantee is worthless because it violates both actual experience and

the principles of physics.

Mr. Kruger. the petticoats of your particular biases are showing, I'm
afraid.

[Dick Pierce[_2_]]

Audio_Empire wrote:
For instance. Lets take two modern, solid-state amplifiers. Let us
stipulate that both are fairly equal in power output, distortion and
frequency response.

Those are pretty vague definitions of "measurement". More likely, they
are "specifications," which, as specifications normally are, quite
inadequate measures of performance. In fact, most specifications
like poer output, distortion and frequency response, serve either or
both of two purposes: 1) marketing or 2) minimum required performance
to legally satisfy advertsising vs performance requirements under
some variety of regulatory and consumer protection requirements.

The latter is the most important, in many case. It says, in
effect, that if a manufacturer can show that the amplifier
meets the published specifications of power output, distortion
and frequency response under conditions which (in most cases),
the manufacturer gets to specify, the manufacturer has proven,
legally, that it has met it's legal oblications in the case of a
disoute with an unhappy customer.

As such, these kinds of measurement far far short of even
a moderatly complete set of performance measurements.

But, let's say that one of the amps has an average
run-of-the-mill power supply while the other has a huge supply with
separate and very large power transformers and separate
supplies for each channel capable of sourcing many more amps of
current to the second amp than is available to the first. Now. lets
operate both amps near their limits with difficult loads. I'll guarantee
you that even though they might measure almost identically in the
above mentioned parameters, under normal circumstances, in these
circumstances, the amp with the largest supply is going to sound better.

And, in those circumstances, they would MOST DEFINITELY NOT
measure the same. Among other things, the measured behavior of
the amplifiers would be radically different driving high powers
in to low impedance loads. And that set of measurements is not
in your list above of power, distortion and frequency response.

--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

[Audio_Empire[_2_]]

On Thursday, December 13, 2012 3:45:23 PM UTC-8, Dick Pierce wrote:
Audio_Empire wrote:

For instance. Lets take two modern, solid-state amplifiers. Let us

stipulate that both are fairly equal in power output, distortion and

frequency response.



Those are pretty vague definitions of "measurement". More likely, they

are "specifications," which, as specifications normally are, quite

inadequate measures of performance. In fact, most specifications

like poer output, distortion and frequency response, serve either or

both of two purposes: 1) marketing or 2) minimum required performance

to legally satisfy advertsising vs performance requirements under

some variety of regulatory and consumer protection requirements.



The latter is the most important, in many case. It says, in

effect, that if a manufacturer can show that the amplifier

meets the published specifications of power output, distortion

and frequency response under conditions which (in most cases),

the manufacturer gets to specify, the manufacturer has proven,

legally, that it has met it's legal oblications in the case of a

disoute with an unhappy customer.



As such, these kinds of measurement far far short of even

a moderatly complete set of performance measurements.



But, let's say that one of the amps has an average

run-of-the-mill power supply while the other has a huge supply with

separate and very large power transformers and separate

supplies for each channel capable of sourcing many more amps of

current to the second amp than is available to the first. Now. lets

operate both amps near their limits with difficult loads. I'll guarantee

you that even though they might measure almost identically in the

above mentioned parameters, under normal circumstances, in these

circumstances, the amp with the largest supply is going to sound better.



And, in those circumstances, they would MOST DEFINITELY NOT

measure the same. Among other things, the measured behavior of

the amplifiers would be radically different driving high powers

in to low impedance loads. And that set of measurements is not

in your list above of power, distortion and frequency response.

Nah. I have two amps here one is a Krell i300 with 150
Watts/Channel, but it has only one power supply with a
single toroid transformer. The other is a Harman-Karden
HK-990, which also has 150 Watts/channel. But the H-K
has TWO huge Toroids (both about 30% larger than the
Krell) and totally separate power supplies for each channel.
The H-K just sounds better, especially at high volumes.

[Dick Pierce[_2_]]

Audio_Empire wrote:
On Thursday, December 13, 2012 3:45:23 PM UTC-8, Dick Pierce wrote:
And, in those circumstances, they would MOST DEFINITELY NOT
measure the same. Among other things, the measured behavior of
the amplifiers would be radically different driving high powers
in to low impedance loads. And that set of measurements is not
in your list above of power, distortion and frequency response.

Nah. I have two amps here one is a Krell i300 with 150
Watts/Channel, but it has only one power supply with a
single toroid transformer. The other is a Harman-Karden
HK-990, which also has 150 Watts/channel. But the H-K
has TWO huge Toroids (both about 30% larger than the
Krell) and totally separate power supplies for each channel.
The H-K just sounds better, especially at high volumes.

You CLEARLY missed the point: your citations of "150 Watts/channel"
are most assuredly NOT measured performance but the manufacturers
specification. You have presented NO evidence to show that, in fact,
they do not measure dramatically different under the conditions
you're claiming.

Specs are not measurements.

--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

[Audio_Empire[_2_]]

On Friday, December 14, 2012 6:21:22 AM UTC-8, Dick Pierce wrote:
Audio_Empire wrote:

On Thursday, December 13, 2012 3:45:23 PM UTC-8, Dick Pierce wrote:

And, in those circumstances, they would MOST DEFINITELY NOT

measure the same. Among other things, the measured behavior of

the amplifiers would be radically different driving high powers

in to low impedance loads. And that set of measurements is not

in your list above of power, distortion and frequency response.



Nah. I have two amps here one is a Krell i300 with 150

Watts/Channel, but it has only one power supply with a

single toroid transformer. The other is a Harman-Karden

HK-990, which also has 150 Watts/channel. But the H-K

has TWO huge Toroids (both about 30% larger than the

Krell) and totally separate power supplies for each channel.

The H-K just sounds better, especially at high volumes.



You CLEARLY missed the point: your citations of "150 Watts/channel"

are most assuredly NOT measured performance but the manufacturers

specification. You have presented NO evidence to show that, in fact,

they do not measure dramatically different under the conditions

you're claiming.



Specs are not measurements.


Actually, you missed MY point which is the same as yours. Published
specs usually don't tell the whole story and improper testing procedures
can obscure that story. People buy on published specs, features, and looks.
Very few have the facilities to do even a cursory measurement in order to
find out what the actual specs are, and whether or not the device of
interest meets those specs. And they certainly don't get access to test
the component before buying it. People have to rely on published tests
and even they often don't do stringent tests (many don't test at all.
They just listen) like measuring output power with both channels driven
to their rated output. Usually they test one channel at a time when doing
these types of tests.

[Arny Krueger[_5_]]

"Audio_Empire" wrote in message
...

Nah. I have two amps here one is a Krell i300 with 150
Watts/Channel, but it has only one power supply with a
single toroid transformer. The other is a Harman-Karden
HK-990, which also has 150 Watts/channel. But the H-K
has TWO huge Toroids (both about 30% larger than the
Krell) and totally separate power supplies for each channel.
The H-K just sounds better, especially at high volumes.

Without any other evidence, I interpret the above as saying: "I have an anti
scientific view of amplifier performance that my unscientific listening
evaluations confirm."

There are many possibly relevant differrences between these amplifiers
presuming that they still both meet orgional specs, and not even that seems
to be known to be true with any degree of objectivity or confidence.

Futhermore we know that personal preferences can be whatever the preferrer
wants them to be and based on whatever the preferred bases them on.

If you wish to be more convincing, provide more convincing evidence!

[Audio_Empire[_2_]]

On Monday, December 17, 2012 7:47:24 PM UTC-8, Arny Krueger wrote:
"Audio_Empire" wrote in message

...



Nah. I have two amps here one is a Krell i300 with 150

Watts/Channel, but it has only one power supply with a

single toroid transformer. The other is a Harman-Karden

HK-990, which also has 150 Watts/channel. But the H-K

has TWO huge Toroids (both about 30% larger than the

Krell) and totally separate power supplies for each channel.

The H-K just sounds better, especially at high volumes.



Without any other evidence, I interpret the above as saying: "I have an anti

scientific view of amplifier performance that my unscientific listening

evaluations confirm."



There are many possibly relevant differrences between these amplifiers

presuming that they still both meet orgional specs, and not even that seems

to be known to be true with any degree of objectivity or confidence.



Futhermore we know that personal preferences can be whatever the preferrer

wants them to be and based on whatever the preferred bases them on.



If you wish to be more convincing, provide more convincing evidence!

Actually, I'm mostly indifferent to convincing people who cannot or will not hear
what I hear. I put it out there as a conversation point, and it provokes conversation.
That's my major interest. I like to see opposing views on things and I enjoy the
conversation.

[Sebastian Kaliszewski]

On 12/13/2012 12:42 PM, Audio_Empire wrote:
On Wednesday, December 12, 2012 5:28:11 PM UTC-8,
wrote:
Per request, the lowdown on amp DBTs. We don=92t need a lengthy list
this time, because old RAHE friend Tom Nousaine did us the favor
of summarizing them for an AES conference paper some years ago:



http://www.aes.org/e-lib/browse.cfm?elib=3D5426



From his conclusion:



=93In summary, there has been no evidence to support the conclusion
that factors other than linear response and output capability
contribute to the sound of well designed power amplifiers...



=93This does not suggest that amplifiers are perfect and they will
never be found to sound different. It does suggest to purchasers of
today's audio amplifiers that as long as the product in question
meets basic traditional measured performance standards, has enough
output capability, and adequate quality of construction, it will be
sonically indistinguishable from all others meeting those
criteria.=94



Once again, Brian Moore=92s textbook, An Introduction to the
Psychology of Hearing, concurs:



=93The basic performance of even a moderately priced hi-fi amplifier
is likely to be so good that improvements in technical
specification would make little audible difference. For example, a
moderately good amplifier will have a frequency response from 20
to 20,000 Hz +/=96 1 dB, distortion less than 1% and a
signal-to-noise ratio greater than 90 dB (for input signals with a
reasonably high level, such as from a CD player). These values are
better than the limits required by the ear.=94



And just for fun, here=92s a DBT from the Matrix HiFi guys that
involves more than just amplifiers, this time in handy English:



http://www.matrixhifi.com/ENG_marco.htm



(Click on Blind Tests, and then on the subsequent link.)



Perhaps the inferior high-end cables masked the superiority of the
high-end amplification?



Once again, no empirically plausible evidence has ever been
presented on the other side.



bob

"This does not suggest that amplifiers are perfect and they will
never be found to sound different."

Of course if one is loaded beynd it's capability it will sound different.


The sound of an amplifier is directly proportional to the extent of
the differences found between them and how far each differs from
theoretical perfection.

For instance. Lets take two modern, solid-state amplifiers. Let us
stipulate that both are fairly equal in power output, distortion and
frequency response. But, let's say that one of the amps has an
average run-of-the-mill power supply while the other has a huge
supply with separate and very large power transformers and separate
supplies for each channel capable of sourcing many more amps of
current to the second amp than is available to the first.


Then eitehr they are not equal in power output (the one with bigger &
better power supply has in fact bigger measured power) or that power
supply is an overkill, a bling, a thing to impress by sight, not by
audio performance.

Now. lets operate both amps near their limits with difficult loads.
I'll guarantee you that even though they might measure almost
identically in the above mentioned parameters, under normal
circumstances, in these circumstances, the amp with the largest
supply is going to sound better.


And an evidence for that?


If they are measured to have neglibile distortion at a given load they
will present neglibile distortion at that load. Or if one has
significant distortion due to power supply inadequate for signal level
required then thy are simply do not have the same power.

rgds
\SK