Came across one of these cheap pre amp channel stips - I figured on giving it a shot. Tested earlier this evening and doesn't actually sound that bad, all except for when you start to press the "in" buttons on the other modules, then signal loss, pops, cracks, drop out - big time.
Seems to be a problem with the pre-amp itself. Further investigation on forums reveal that these particular units are all but famous for developing this condition (especially with the switches) after a year or so.
Edited by wjgypsy (10/10/15 12:08 AM)