Thanks for the replies.
The speaker wires are actually decent/overkill and very short. The amp is right between them, and there is probably less than a foot of wire to each speaker. I am a little concerned about the plug that attaches them to the amp. - I'll double check there.
I believe that the interference is from the power side of things. Obviously, when you unplug the light, the buzz stops. The amp and the light share a power strip, and the light is ultra cheap, so electrically noisy ballast is my first thought. Maybe there is some sort of isolator that I can plug in between the light and the powerstrip...
I'm open to any other thoughts.
EDIT: added a nice pic of "EMF Man" he is the superhero of the Electromagnetic Field suppression world
