I also have a slight hum in my unit. My hum has to be from dirty power because it isn't always there. It will be there when I turn it on but then will disappear and reappear when it is on. My Parasound that I replaced used to intermittenly have a hum also that when it was there was louder than the Outlaws. I didn't think it was possible because I loved my parasound, But the Outlaw sounds even better than the Parasound. Cleaner, clearer, and a more uniform soundstage all around.