I'm not quite sure what you mean, is that like the ground on a turntable? If so then no. I have shielded Hosa studio cables, believe they are balanced, and 1/4 inch. I know the esi has unbalanced, so do I need to use unbalanced cables? The thing is my old korg x3 has unbalanced and sounds good with the same cables.
I've tried changing mixer channels, different cables, using the sub outs on the esi, and still there is a bad hum.