"Bob-Stanton" wrote in message
om

"Arny Krueger" wrote in message
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"Bob-Stanton" wrote in message
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"Arny Krueger" wrote in message

And you haven't given us one example of a low cost amplifier with
audible distortion when operated within its ratings.

How about any Radio Shack PA amplifier?

How about it. Where are your listening test results?

I don't put much stock in judging amplifiers by listening tests.

Name some more reliable way to determine the presence of audible distortion.

Look at the published distortion figures from Radio Shack. The MPA-40
has 10% THD, at 20 Watts. You don't need a listening panel of fifty
people with golden ears, in order to make the wild guess that the
amplifier is less than totally transparent!

Let's apply a little common sense here. Obviously they tolerate a lot of
distortion to jack up the power rating. 10% THD is pretty far into clipping.
I guess I should have thrown in the usual disclaimer about clipping.

What does this piece perform like at say 10 wpc, where it is more likely to
be used?

This is related to a pretty common audio NG question where people ask what
would be the audible difference between a receiver rated at 0.05% and 1%
THD. They could both be the same receiver, with different rated power!

If the receiver is powerful enough (say 100 wpc) its probably not going to
be listened to much anywhere near rated power. At normal listening levels,
it's that receiver rated at 0.05%, and the 1% THD rating is completely
irrelevant.

What's ironic is that I may have a MPA-40 on hand. If it's what I think, I
recently took one out of service. It was being used to supply sound
reinforcement (i.e., play music and voice) via two RS Minimus 7 speakers
(low efficiency, and one burned out tweeter) for a room that is 20 x 50 with
carpeting and a 15' high acoustical ceiling (pretty dead). The whole works
sounded like the dickens, but it was a horribly misengineered system. I
replaced it with a 75 wpc amp and a pair of Infinity monitors. People like
it, now.

There's a fair chance that if not operated in clipping, the MPS-40 is
sonically transparent.