I used to have an older sub that would hum when no signal was sent to it. So I wired up a 120VAC relay to a duplex receptacle. The relay was powered by the receiver's switched 120VAC outlet. When the receiver was turned on, it would trigger the relay, which would energize the duplex receptacle. Really simple and solved my humming problem. You could do something similar. But, like everyone mentioned, it is not really needed.