I've recently built my first sonosub. It's works great and in general I'm very happy with it. The only annoyance is the amp. It hummmmmmms. Not loud, but enough bother me if I'm not watching TV. Is there anyway to get rid of the humming? I initially thought of plugging the amp into my reciever to be switched on with the receivers power. But no good, it doesn't have a grounded plug. Any Ideas?