"Arfa Daily" wrote in message
...
"William Sommerwerck" wrote in message
...

If you have a distortion meter -- especially one that can show the
levels of each harmonic (eg, an audio spectrum analyzer) -- you
might try adjusting for the lowest distortion or the least odd-order
distortion.

I do have one, but it only shows THD. I was expecting the figure to
be somewhere between 20 and 50mA, and was erring on the side
of caution and cool running with 20mA. It's now set for about 30 per
Trevor's useful info, and heatsinks are just barely off room temp at idle.
I doubt that there would be too much to be measured as a difference
in THD between 20 and 30mA, and the owner probably wouldn't be
able to tell the difference... :-)

I'd be foolish to suggest there even _might_ be an audible difference.
However, the harmonic-distortion spectrum of transistor amplifiers can vary
quite weirdly with bias and signal level.