"Patrick Turner" wrote in message
Ian Bell wrote:
Don't know if anyone is interested but I got this little
snippet in the email form Elektor today:
http://tinyurl.com/82upa5
He seems to have discovered yet another type of
distortion which he has christened Dynamic Damping
Factor Distortion (DDFD).
Well, the DF does change during a wave cycle. Ra isn't
constant at all points; if it was, there'd be less THD
and IMD.
DF changes during a wave cycle is of course always there if the amp is
nonlinear, and all amps are at least a tiny bit nonlinear. It is only going
to have the possibiilty of being an audible problem with amplifiers that
have quite a bit of nonlinear distortion. Whether you would hear this second
order effect among the primary effects of all that nonlinearity seems
doubtful.