Isolation Transformer - Use with Cheater Plug

Thx again. And the humor went over my head - I have no idea what you are talking about :)
Jea48 - Yes, without the cheater plugs and even inserted into the same outlet I get the hum. I replaced a Parasound with a McCormack power amp and that started my having this problem. Cheater plugs do solve the problem but I had read where an isolation transformer might solve it as well and there would be no possibility of a nasty shock using that method.
It appears from what you guys are telling me, it that I am still better off to have the pair plugged into the Tripp-lite using the cheater plugs than to go back to having the pair plugged directly into the outlet. It reduces the chance of a lethal shock.

Forgot to say that I do have Directv and audio is connected to the preamp via RCA jacks. So maybe a RCA ground isolation device is what I really need.

02-22-09: Hhawk
Forgot to say that I do have Directv and audio is connected to the preamp via RCA jacks. So maybe a RCA ground isolation device is what I really need.

Could very well be the source of the ground loop hum....
For lightning protection the SAT system has a lightning protection arrestor. The cable/s from the SAT dish connects to the arrestor then exits the arrestor and runs on into your home.

Some SAT installers use an outside driven ground rod to connect the lightning arrestor to earth. This will cause ground loop hum.

Temporarily disconnect the Directv ics from the preamp! Check for hum.....

Still have hum?
Just to make sure you are isolating the SAT 100% from your audio system disconnect the RG6 coax/s, (at the receiver), that comes from the dish to the SAT receiver. You may have two RG6 coaxes if you have a DVR.

Post back the results.