Ground loop feedback

Recently, I switched amps from Krell 450mxc to Lamm M1.2. Upon hooking them up, I found that I had a ground loop on my system causing a fairly audible hum in my speakers. Since, I have tried everything to eliminate this noise. No success yet!

As background, an Equitech panel that is remote delivers all power to the system. There are separate circuits to each amp along with separate circuits to my front end (DCS stuff on a filtered circuit and an analog EQ is on a separate unfiltered circuit). This ground loop did not occur at all with the Krell equipment.

I have tried the following to rectify the situation:
-Lifted the grounds (with cheater plugs) on each amp and grounded the amps separately (they have ground lugs) to the same ground.
-Lifted the grounds (with cheater plugs) on each amp and grounded the amps separately to the same ground back to the receptacle where the DCS equipment is plugged in to.
-Plugged the amps into a separate (house) circuit that is common between the two amps.

I guess I can try a couple of more fixes, but at this point I’m not sure much is going to help. One thing that I have noticed is that when the interconnects are connected to the amps, even if they are not plugged into the front end (DCS), the problem is much worse.

Does anyone have experience with this problem and what have you done (tried) to do to fix it.

(This problem is occuring with Wilson Speakers and Transparent cables, both speaker and interconnects)