Ok, I have my nes (bare board) connected to my tv. It is powered by 7.2+ volts (depending on the power supply I use) going through the 7805. However whenever I turn it on, there is a noticable buzz in the background that changes pitch when something happens on the screen. At first I thought this were a shielding issue, but I discovered that I can get clear audio when hooking up directly 5v from a 5v power adapter to the nes. I have tried several different 7805s now and am at my wits end. I need to get this problem fixed pretty soon, so any help is appreciated.