Hi,

I had a serious hum issue with with my 970 and both of my subs in two different systems. I discovered the culprit by disconnecting source gear from the 970 one at a time until the hum went away.

In my case the culprit was the cable feed entering my home. when I disconnected the coax from my cable box, the hum disappeared. I had an electrician check it out and it was not grounded at all at the point of entry. When he tied the cable POE ground to same ground as the rest of the house wiring it helped some but there was still some noise. What took me the rest of the way was a ground loop isolation transformer. I have two installed, one on my HT (Jensen JEN-VRD1FF)and one in my bedroom (Dayton VIT-1), where I have cable boxes. No more hum.

Short story long, discovering the source of hum is a process; you need to be methodical and only change one thing at a time to be sure to get to the source. Once you've found the source, there may be another process waiting for you to figure out the fix. I hope it's as simple for you as it was for me. Google is your friend.

Best of luck,
Tony.