One product that can fix the hum is the Ebtech Hum-X Eliminator. It can be found in guitar stores or on-line. It's a filter that plugs into the wall outlet. Then you plug your amp into the filter. I had an annoying hum with my new 7500 that seemed to be tied to my HDMI cables from my video processor. By plugging the Hum-X equipped amp and the video processor into the same 20amp dedicated line completely eliminated all hums and buzzes. The Hum-X Eliminator runs about $30 or so online.