Weird audio engineering problem

[Chaotic42]

We have a Crown D-75A amplifier (link) that produces a weird hum when the right channel is between 50 and about 5 (I'm not sure what these are units of, but it's some measure of resistance. 0 is the loudest).

Anyone have any ideas? I don't know if our engineer has called them, but he knows about it. It's been doing it for about 9 months now.

 

[ArmenK]

Possibly a ground loop problem. Try using a "cheater plug" which is a 3 prong to 2 prong power cord adapter.

 

[Chaotic42]

Whoa, I just checked the power plug.

It's a 3 outlet/3 prong adapter plugged into a power strip, with the amp plugged in the 3/3 outlet. The thing is, it's upside down with the groud pin bent slightly and handing out.

WTF?