I always put my fx between bass & amp, but after reading this I have tried putting it in the loop.
+ side, I lose most of the high pitched squeal that was there from using the Godlyke PSU on the MF101 (the VLE got rid of this by turning to just above 9 oclock).
- side, I need to pull the head out the combo to change the jumper as I get clean signal mixed with fx signal. Might suit some folk, doesn't suit me. But I'll try changing the jumper.