O.K., so I'm not the brightest guy in the world. I just simply disconnected the cable from the cable box and that did it. No more "buzzzz." Regardless of whether any of the t.v. interconnects were attached to the pre-pro or not had nothing to do with it. I guess the cable was introducing a ground loop into the A.C. outlets, I guess. I obviously don't know much about this stuff. All I know is that as soon as the cable seperated from the cable box the noise went away, and I had nothing but quiet throughout the system.

Don't know if this will help anyone but it worked for me. At least for now. Now i guess I need to