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Audio amplifier design trivial?
"Nousaine" wrote in message
...
"normanstrong" wrote:
...snips.....
"John Atkinson" wrote in message
I see statements like this from time to time, yet I am not so
sure
that audio design is "trivial." There are not many other design
fields
where an amplifier: has to provide up to 30dB of voltage gain;
act as a
voltage source into a wide and arbitrary range of load
impedances
and do so in an unconditionally stable manner; have a passband
noise
contribution at least 90dB down from 1W into 8 ohms, no matter
what
its voltage gain and ultimate power delivery; have distortion
components under all load conditions that are below the
threshold of
hearing no matter what the program material is; and do all the
above
over at least three-decade, ie, a 10-octave passband.
Thoughts, gentlemen? I would suggest that designing, say, a
typical RF
amplifier is, by comparison, "trivial" but, of course, I may
just be
missing something :-)
I don't know if Mr Atkinson is missing anything. But I wonder exactly how
it is
that with the exception of high-ouput impedance amplifiers that exactly NO
ONE
hasd ever shown in a reasonably well bias-controlled experiment (including
Mr
Atkinson's; indeed his personally conducted large trial experiments showed
that
even with high-output impedance amplifiers there was no sonic difference)
that
modern amplfiers have any sound of their own.
Sure, take my words out of context.
You left out the previous part that qualifies them:
"Audiophiles don't realize that audio is an extremely small
part of electrical engineering and that very, very few schools
even
teach courses in the subject. It isn't where the money is, nor is
it
where the interest is for EE students. EEs like to make ICs or
design
computers or work in motor control or design antennas or work in
telecom."
My apologies "audioguy" but I don't see how this paragraph changes
the
meaning of the words you wrote about audio amplifier design. It
doesn't
matter _ why_ electronic engineers feel audio is a "trivial"
application,
only that they do, and that is what I was addressing. Note that I
feel
that audio amplifier design is far from trivial. If you look at the
list of attributes I listed for an ideal audio amplifier, I can
think of
almost none, of all the designs I have tested for Stereophile, that
achieve that level of performance.
John Atkinson
Editor, Stereophile
OK; which ones that you recommend have been shown to sound different with
a
bias controlled listening test?
Certainly more than half of the requirements you placed on your
amplifier design detailed in your first reply to this header disappear
if the designer knows the characteristics of the source and load ahead
of time. It is for this reason that I forever wonder at how few
speakers come with their own amplifier--at least in the home hi-fi
industry.
Norm Strong
Actually the best-performing speaker I've tested DO come with their own
amplifiers and application specific EQ.
I wonder what Mr Atkinson's experience may be in this regard.
What speaker do you refer to?
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