Thanks AvFan.

I agree that the TV, a Samsung 67" 1080P DLP, is a big part of my problem. But I have nothing connected to it except power and the HDMI cable going to my Denon 4306 that I am using as a pre/pro. I don't have cable, although I do have satellite RG6 lines run into my sat receiver, a DISH VIP622.

I have previously gone through a full ground debug exercise of disconnecting everything and starting at my amp and working my way backward adding things to find when the hum starts. At that point 90% of the hum was due to the loop through the TV even with no cable connections. But its been a long time and I've made a few config changes to my system so I'll do it again.

I'll post results. I also ordered one of those Ebtech HumX widgets so I'll try that at out as well and post the results.

Right now all my gear is connected into a single Brickwall 20A audio surge/distribution rack mount. But if I can't solve this hum problem through some simple measures like the HumX, I'll have to buy some more expensive filter/conditioner or whatever it takes.

At this point I'm so frustrated I'll spend just about anything to make it go away. GRRRRRRRR

This problem would have been solved for the future for everyone if the HDMI inventors had instead choosen an optical connection rather than electrical, since optical maintains "galvanic isolation". Fiber optic cables have the nice benefit of providing electrical isolation so no ground currents or other noise of any kind can pass over the cable. It would be a great thing to have a system built with nothing but optical connections between all units for data movement until the final high quality analog-to-digital conversion, at which point the signal path to the amp should be differential (aka balanced). A system designed this way would be VERY noise immune. Oh well.

Thanks,
Dan

p.s. - Outlaws, if you had an HDMI switching pre/pro with conversion of the analog inputs to HDMI I would dump my Denon 4306 on ebay and buy it from you immediately. To get the differential outputs and help solve this plague on my existance . . .