Curtis- I'm curious to know if Alan's suggestions helped you out with this hum issue. I am now experiencing the same hum problem with my setup. I specifically can trace it to one component, which is my Adcom GDD-1 (digital decoder). When I turn it off, it goes away completely.

I'm going to try Alan's suggestion of reversing the plug to see if that's what the issue is. I'm really hoping that will do the trick. I'll try it tonight and report back.

-Kevin