The buzz is known as a '60Hz' humm. This is a ground issue and can be resolved quite simply by using a ground loop isolator. Let me know specifics about your setup and I can advise you further. When you experience the buzz are you getting the audio input signal from another component or PC to your receiver ? I recently fixed this issue when playing music from my PC on my receiver. I added the ground loop isolator ($18) along the RCA line to my receiver and the sound is completely gone.
Thanks,
Steve
"Failure is a detour, not a dead end-street." -Zig Ziglar