RFI from steel TV bracket?

What *other* changes did you do?

No other changes :^)

What happens if you unplug the interconnects from the inputs to the amps? Do they still buzz?

Right now I'm sticking to my original theory, only substitute 'interconnects' for 'speaker cables', and since the ICs are single-ended, this makes a lot more sense.

When I unplug the output from the pre-amp......the hum is still coming from the speaker.
But when I unplug the input to the amp (with the output still connected to the preamp)......the hum disappears :^)
If you're right.......any solutions other than removing the steel wall bracket?
Thanks
Henry

But when I unplug the input to the amp (with the output still connected to the preamp)......the hum disappears

I still think there is a possibility that the interconnects that go from the preamp to the amp my not be shielded enough for the new environment. Try a different pair (if you haven't already) between these two (amp and preamp) that may have better shielding, or a different design. Last resort (don't laugh), even some budget ones from Radio Shack, or even a big box store just temporarily to see if this can be the problem.

Hifihvn makes a good suggestion. You might be surprised how good some of Radio Shack's cables actually are.

Now. Since you are running single-ended cables, if there is a hum source (like the primitive transformer thing I mentioned), even if the cables are shielded you will still get a hum as single-ended cables have no 'Common mode rejection'. (IOW if you have balanced cables you may not have noticed a problem.)

So what I would do is temporarily reroute your cables so they are no-where near that bracket and for that matter, any power cords too. If you have to shut down everything but the amps, go ahead a do so for the purposes of this test. So hopefully you won't have to go to Radio Shack :)