So, I have an old Interfax Harmonic Percolator copy and I decided put swap out the x-wing switch for a Blue 3PDT switch and a LED (using the diagram from GGG). Everything seems to be working OK (the pedal bypasses correctly and it sounds just as good as it ever has), but if I don't have anything plugged into it, and hit the switch, the LED turns on. Is this normal, or did I mess something up?
did you change the wiring to the input jack? if you did you may not have it setup right...
you probably want it so when you plug in your jack, it completes the circuit, and enables you to turn on the pedal, do a search for a diagram on input jack wiring.
(http://www.diystompboxes.com/beginner/circswled.jpg)
this is from the beginners section of the forum, all credit to aron.