I turned off the receiver, still humming, and then unplugged it. The humming stopped for about 3 seconds and then started back up. I unplugged all the other components which gave negative results. I unplugged the sub and plugged it into another outlet and the hum was 10x louder!!! I need help Would a power conditioner help or power strip???

Lots of speakers from many
manufactures...mostly Axiom