Thanks for your opinion. However I have a dedicated HT room and all circuits in that room are prioritized specifically FOR that room. There are no appliances. All of the equipment is connected to a Furman line conditioner except for the 7700. I have four different circuits that I use for my equipment. I have two 20amp circuits and two 15amp circuits.
All circuits were tested for correct wiring. No problems.

I tried all circuits without the extension cord getting the dang HUM. I also tried all circuits using the extension cord and everything is quiet as a mouse.

What are the chances that all four circuits breakers are bad, highly doubtful with this scenario.

Thanks for the advice. I might be forced to bring in an electrician but for now I want to try and solve this problem myself with a little help from my friends.

Thanks again