In article , Form@C
wrote:
On Sun, 04 Jan 2004 11:09:48 +0000, Ian Molton wrote:

On Sun, 04 Jan 2004 08:27:50 GMT "Form@C" wrote:

It's no use turning down a 100-200W monster amp because you arn't
running them at their best.

what?

Sorry, it wasn't very clear was it? What I meant to say is that "high"
power amps are usually designed and set up to produce their best results
an appreciable way up to their rated power output.

That isn't my own experience. Nor was it what I intended when designing
200Wpc power amps myself. :-)

The purpose of the high power (and voltage/current) ratings is to ensure
the amp can be used in wider range of circumstances, hence encompassing
higher powers and more awkward/less efficient loads. Thus the idea is that
the amp should sound good over a wider range of levels, from low to high.
If it does not sound right at low power, then something is wrong with it,
irrespective of its power rating.


They won't perform at their best at a very low percentage of that level.
I *know* that many are *supposed* to be class A at low levels, but they
are generally not designed as class A amps, and are not really running
as such (the output stage quiescent current is usually too low to allow
correct class A operation on a class AB amp).

In general, class AB amps are not designed as class A or class B. This
isn't really a matter of the power rating as such. However...

The quiescent current in most of the good high-power amps I have known was
similar to, or higher, than in lower power amps. Hence your statement about
"usually too low" could be argued to probably apply more to low power amps
than to high power ones. High power amps should work nicely at low powers
in terms of the 'class A at low powers' argument. Also, using the devices
with lower levels of collector-emitter (or equivalent) variation in
fractional terms also should help here. I would not personally take this
"class A at low power" argument very far, though, as the reality isn't
really described by this. The problems may be elsewhere.

Thus it is a mistake to judge low-power audio systems by simply turning
down the volume on existing "high" power equipment & changing the
speakers for more sensitive ones.

Depends upon the amp and the speakers. :-)

FWIW I use +200Wpc amps with speakers like ESL63's and before that ESL57's.
Been doing this for around 20 years, now. Generally I only play at quite
low mean power levels. The results sound fine to me even though I never go
anywhere near 200 Wpc. Having an amp that can drive difficult loads means
the amp is finding this task easy, even when I once used parallel pairs of
ESL57's for a while. :-)

Slainte,

Jim

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