I finally isolated the noise in my system to my QSC sub amp. The noise doesn't go away when the power is turned off on the amp, it goes away when I unplug it. "Bob, from QSC where art thou?" Can I unplug the internal fan? Is there a capacitor from Parts Express that will eliminate the very loud 60Hz hum? TIA for any remedy. It's a good amp, but man is it loud!