I've given up on having the one board that does it all, so I'm going to completely rearrange it to suit the gig. Right now my board goes like so: Bass >> OC-2 >> DOD FX92 effect out>> Copilot Orbit >> SA BEF Pro >> A/B-Y DOD FX92 clean out >> A/B-Y A/B-Y >> LS-2 [EHX DMM in loop] >> amp Everything gets power off a voodoo pp2+; the A/B-Y is passive and from Morley; the FX92 is the old version of the Bass Grunge (which rocks). The issue is that in this setup I get an oscillation/feedback tone when Y is selected and either the Orbit, the FX92, or both are on. Switching the clean and dirt outs of the FX92 eliminates this, but does not result in the desired signal chain. Ideally, I want to be able to switch between clean/OC-2, OC-2 + dirt & filters, and a blend. So, what's causing the feedback? How else can I arrange this board to give me what I want (the option of clean, clean/dirty blend, or just dirty)? Oh, and before anyone mentions it, the DMM's clean and echo outs appear to have opposite polarities -- when I used the A/B-Y with those outputs, I got lower volume with both on.