I think Uncle Dave means you got a bad Nano. It sounds like it to me. I hope you figure it out though. As Uncle Dave also mentioned, sometimes plugging instruments into the same power strip an cause humming/buzzing. I don't exactly know the physics behind such things, but I do know this. In my rig at home, If I plug any piece of equipment with a three prong plug into one particular power strip, I get a buzzing into my mixer and out of my amps. So I keep all three prong plugs in a different power strip and I get no buzz at all. Vierd, yesh, yesh.. very vierd.