I'll have to find one of those cheater plugs. I think my dad has one or two somewhere. Otherwise, I'll pick one up. That's what you're talking about, right? So I should just hook the amp up to the wall with one of those to see if the hum goes away?

And yes, no hum with the receiver powering the speakers. No appreciable hum, anyway. If I turn the volume way up, I can hear a tiny bit, as you'd expect. The hum on the amp is unrelated to volume level.

I'm also waiting to hear more from JC who's been talking to Andrew. I really appreciate all of the help, guys.