[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.

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+ Dick Pierce |
+ Professional Audio Development |
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