Out of three defective Marantz receivers I purchased and returned, two exhibited the popping noise. This noise is much louder than the quiet "tick" one hears when changing sources on other brands - it seems to be a capacitor discharge that builds after about 20 minutes of listening at average or higher volume. After sufficient time has past, changing sources or reducing the volume to zero results in a fairly loud "pop." I'd like to find out how widespread this problem is. If you own one of the new receivers (except the 8200, which reportedly does not experience this), please report if yours has this defect or not.