Re: phase 90 true bypass..anyone?
Search diystompboxes.com. There's a detailed explanation in the forum complete with pictures. You'll have to search for it though.
IMO, it's much easier to just build a loop box for it or put a buffer between the circuit out and the output jack (I did). Or, just get the EVH model. It's got a MUCH better bypass circuit and doesn't suck tone.