"PeterDope"

Clearly more than some people (I'll exclude you, since you do know
what you are doing.) bottom line is that that test is very limited,
and won't show the problem that he's experiencing which is distortion
at higher volume levels...


** On the contrary - the OP spoke of a " buzzy distortion " with NO signal
going through the unit.

Given that the speaker is not poling against the magnet structure nor has
loose turns on the voice coil ( his tap and pull test shows that) the odds
are very high that the problem is with the driving amp.


..... Phil