Quote Originally Posted by Chops View Post
MusicHead,

Thanks for the explanation....

I now have a hum in the subwoofer starting to be noticeable at about 1/2 volume. The receiver is off
If I remove the 75ft shielded coaxial RCA cable it goes away. I have moved my sub cable so that it is not near any of my speaker wires and I still get the hum. I have also tried plugging the sub into the same outlet as my receiver and I still get the hum.

My house is over 150 years old so it does not have grounds even though the outlets except plugs with a ground.

I checked the internet for the suggestions that I tried above. One suggestion that I have not done is try a
sub isolation filter that blue jeans cable sells for $50.00. The RCA is plugged into one end and another RCA on the other end that goes into the sub.

Any suggestions will be appreciated.

Thanks in advance
Chops
I have never had a ground loop hum in my system, so I don't have firsthand experience with it. But, this sounds like it lines up with what others have said, when they have had a ground loop hum. Here is a troubleshooting link that might help.

http://www.audioholics.com/home-thea...m-hum-and-buzz