If it is a polarity problem, it could be in the outlet that the amp
is plugged into at home.



Just yesterday had a hum problem caused by the infamous "yellow glue turned
brown"

The glue was apparently conductive enough to couple to a signal lead right
at the edge of the goop.

Strangely, the hum was 60 hz instead of 120. Still haven't figured out that
part.


Mark Z.