"Pooh Bear" wrote in message
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Arny Krueger wrote:

"Pooh Bear" wrote in message
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Arny Krueger wrote:

"Pooh Bear" wrote in message
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Arny Krueger wrote:

When distortion is below about 0.08%, there just isn't any way to
hear
it.

I used to think you could read a spec sheet that way too.

Unfortunately most thd specs are measured at power levels that are
unrepresentative of normal listening.

What sort of deviation are you talking about?

Deviation ? Funny word to describe it.

Say, an amplifier's thd is measured @100W yet typical listening level
may
be
~ 1W. The data sheet thd is essentially useless. For many amplifiers
the
1W
region is just about the worst possible listening level on account of
crossover issues.

It's been maybe 30 years since I've seen a SS amp in good repair that
demonstrated crossover distortion.

You need to look at the distortion analyser output.

Sure, simple measurements show THD+N
increasing at low levels, but it is the hum and noise that drives the
measurements up.

Forget hum - it shouldn't be there in any decent modern design.

Yes - noise does drive up the figure but simple examination of the
analyser
output on a scope wil show shedloads of crossover on most 'run of the
mill'
amplifiers.

An experienced eye ( such as mine ) can interpret the waveform rather
well.

Look Graham I was probably looking at crossover distortion from SS before
you were born. ;-)

Furthermore, crossover distortion shows up like a sore thumb on a spectrum
analyzer - all the high order garbage.

The only circuitry I've seen that's effectively free of the effect is a
mosfet
output stage - optimally biased.

I just don't know what srt of amps you've been looking at.

This includes cheap IC chips, cheap receivers, and cheap
autosound amps.

The IC chips are frequently the worst examples.

Please name a readily available modern chip that is offensive. I'll run
right out and buy one and test it.