"Arny Krueger" wrote in message
...
"Iain M Churches" wrote in message

"Stewart Pinkerton" wrote in message
...
(huge snip)

Agreed, I have never found a situation where 0.1% of low-order THD
was audible.

Thanks for that Stewart. This was the information I tried to
elicit from Arny. Even good valve amps can often do quite a
bit better than 0.1% THD (mainly 2H)

IME 0.1% is right on the edge. The best way that I've found is to use the
keys jangling natural sound, high-pass filtered at say 6 KHz. I don't
recall if I could ABX it at just above an amount of second order
nonlinear distortion that would correspond to 0.1 THD, or just below it.
But, it was close.

I have been trying to think what the closest sound equivalent to
jangling keys that one might come across in music (leaving out
Stockhausen for the moment:-) Perhaps a "zizzle" (rivet)
cymbal or a shaken tambourine? Triangles and glockenspiels
cannot really be counted when reproducing a single fundamental,
although they do tend to distort easily.

Iain