Denon UD-M30 humming problem

[rmunson]

Hi guys -
I have a nice little denon UD-M30 bookshelf stereo system. It works fine but I just have one complaint - with the volume set to 0 I hear a humming through the speakers.

I have to get the volume up to about 4 or 5 before the music covers the hum - the hum doesn't increase as I turn up the sound.

Any ideas on what would cause humming on a modern SS receiver?

Thanks,
Reed