As it turns out (found it on the Kenwood message board) the display on the receiver causes a buzz, if you turn down the display with the dimmer button on the receiver the buzz goes away. There is also a second buzz that comes in if you turn the receiver up past -28Db, that is related to the digital input jacks on the back of the receiver. If you jiggle the inputs the buzz goes away. The buzz some times returns though, just jiggle the inputs again to get rid of it.