I have an older Sony subwoofer that has been giving me trouble lately. I end up having to turn it off and back to reset it as it will emit a continuous humming sound (very loud as if it is getting a continual heavy input from the receiver) even when the audio output doesn't warrant the activity. Since it is somewhat random I don't think it can be a ground loop issue--I do have it plugged into the same outlet as the receiver. I tried the polyfil mod, and also bought a new cable (Monster) and that didn't help. If the sub is toast, I can accept that. However, I'd hate to buy another sub and find out it is the receiver or something. Am I possibly overlooking something? It is strange because sometimes I can get through an entire movie with no problem and other times it will need a "reset" several times.