So my MKII Pro seems to be quite incompatible with my Dunlop Crybaby Classic (w/fasel). When my guitar is at full volume, I can play through my tonebender without a problem. However, when I put the switched-on wah in front of it, and play with my guitar volume at 10, the tonebender cuts out nearly instantaneously. When I turn my guitar volume to 2, the wah and MKII work together fine. Why is this? Is it possible that my wah is just buffering the output way too much? Is it also possible that, since the MKII has a positive ground, and the wah has a negative ground, that they're incompatible for some reason?
Do the output buffer for the wah, then you won't suffer those kind of problems. Schematic can be found at fuzzcentral.tripod.com, there check the axis wah project.