Dear cp1966,

I have been actively following this thread because I am experiencing a nearly identical issue (HDMI induced buzz), except that it is occurring with my Model 7900. I waited until now to respond because I didn't want to interfere with the troubleshooting of your issue. Bottom line: after conducting a nearly identical troubleshooting procedure as you, I will be returning the amp. Briefly, I have a Denon AVR3808-ci receiver (RCA preouts only), 3 sources all of which are connected by HDMI (65" Panasonic Plasma, Denon Blu-ray, and a Motorola DVR). Just like your situation, the buzz is caused by HDMI cables. With everything hooked up, the buzz is so loud that it is audible 15 feet away. When I remove the HDMI out to the plasma TV, the buzz decreases 50%, and when I remove the HDMI in from the DVR, the buzz stops entirely. Like you, I have swapped out cables, used cheater plugs, removed my Panamax conditioner, etc., but nothing stops the buzz (other than removing the aforementioned HDMI cables). However, again like you, when I take the Outlaw out of the picture and hook everything to my AVR, pindrop silence! Similarly, and even more telling, when I use my Emotiva XPA-5 as the amp, it too is pindrop silent using the same connections.

Given our nearly identical issues, I conclude that the giant transformers in these amps are effectively antennas that attract unwanted frequencies. Our situations are not consistent with a ground issue.

I am very disappointed that I have to return the amp, because it is simply amazing. Even at very low listening levels, 50 db below reference, the bass is significantly tighter than my Emotiva and the midrange is also much more clear. I can't even imagine the sonic improvement at levels approaching reference.

Good luck with your issues, and if you would like to chat further offline, let me know.