I've built this effect before and did not have a problem, but recently I decided to build it again and everything sounds great after I bias w/ the trim pots but every time I disconnect it from a power source and plug it back in the biasing seems to reset completely and i get no sound until I start adjusting the trim pots.
Any idea what might be happening?
Check your solder joints on and around the trim pots ;)
Reflow them if necessary...