Hello there. I've been, over time, re-wiring/re-patching our sound rack. One thing I have run into, is there is a ground signal all the time coming out of our loudspeaker arrays. The ground loop starts in the rack. There isn't any problem with inputs into the mixer, or anything going out of the mixer. All of the outputs on the mixer go over CAT5 to an expansion card on the rack. In a sense, the rack has no outside ground influence. However, there is a ground loop starting somewhere in the rack. I'm trying to identify the source of the problem, or find some way to eliminate the issue. We have wireless mic receivers, antenna distribution units, a bi amp distribution system, and 7 power amps on our rack. All of which, are connected to the same ground circuit. Hoping to get some help on this. I'll attach pictures, although good luck deciphering the back. Haha.