Well mrlin you dont show where you are but that is fairly normal with some amplifiers. I have a friend that receives CB radio on his speakers at times. The only way to get rid of this is to put a better shield around the amp inside the box and around the audio cables going to it.


P.S. I do maint work at a tv station in detroit so I am very familiar with this sort of thing.


P.P.S. Actually the transistors inside the amp will act as diodes as well.