When I said I "I have disconnected all of the speakers, and I still get the buzz" I meant I have disconnected all of the inputs and still get the buzz.
I have a older yamaha receiver (early 2000s), and I keep getting a highish pitched buzz from the speakers. I have disconnected all of the speakers, and I still get the buzz. I have tried disconnecting them one by one and have the buzz no matter which one is plugged in alone. It doesn't have a ground so I put a 3-2 prong adapter ground on it. No change. Tried the same 3 to 2 prong adapter ground on the television and no change. I plugged only the receiver into the outlet with the speakers and still got the buzz with no inputs connected. I believe I've narrowed it down to the receiver, but is there anything else I can do to try and fix/troubleshoot it?