My 7125 emits a mechanical buzz, presumably from its power transformer, when my TV (Panasonic TC-P65VT50) is on. The buzz varies in level depending mainly on the brightness of the image at the moment, but it can be clearly audible at 15 feet if the soundtrack is fairly quiet at the time or off. The most interesting thing about this is that it occurs even if the TV is not connected to anything other than AC. I can disconnect all cables from the TV, run slides from a USB stick, turn on the amp, and the amp will buzz. (The Model 2200 I use as a subwoofer amp does the same, but it's behind a door, so its buzz is not really noticeable unless I open the door and listen for it.) Anyone have any ideas as to what might be causing this or how I can eliminate, or at least reduce, the buzz?

Thanks.