I am finishing my basement to include theatre room and bar area. Everything was coming along great, plenty of 20A circuits and I tested my electronics downstairs to make sure there was no buzzing present before I put up the drywall.
I started working on the accent lighting which includes a few sets of dimmers. When the dimmers are on in the basement, all my electronics upstairs exhibit a horrible buzzing noise. You can even hear the TV's power supply buzzing. I turn the dimmers off downstairs and the buzzing stops.
I can't wrap my head around what is going on here, the upstairs and downstairs are on separate circuits. They both are connected to a common ground, that being the main ground for the house.
This sounds like the RFI interference typical of solid-state dimmers. The Lutron units should have integral RFI filters, but you may have a bad one. Disconnect them one at a time to see if the noise can be associated with one of the dimmers. Otherwise you can try outboard RFI filter(s) on the line side of the dimmers. Next would be to try to find a quieter dimmer.
I had dimmer switches in my office within 5 ft of my equipment stack. When I upgraded from a Yamaha to a Denon receiver I picked up an annoying buzz. Finally discovered the source and decided I could live without the dimmers. Buzz is gone.
Will check it out tonight. It probably doesn't help that I have 7 total dimmers installed. Pardon my ignorance but are there any dimmers that don't produce RFI? LeBon mentioned this was typical behavior of solid-state dimmers as if there might be another type not susceptible to RFI.
My eperience has been that the Lutron dimmers are OK with respect to RFI, but that the cheapies omit the RFI filtering. I understand that yours are Lutron. That's why I suspect a bad dimmer (failure in the RFI filter section).