Once you’ve finished the circuit it makes sense to test is before starting on the switch and LED
wiring. It’ll cut down troubleshooting time in the long run. If the circuit works at this stage, but it
doesn’t once you wire up the switch - guess what? You’ve probably made a mistake with the switch.
Before you start, take a small screwdriver and position the biasing preset in the middle of its turn.
You’ll adjust this shortly.
Refer to the appropriate diagram depending on the polarity of your build. Solder some nice, long
lengths of wire to the board connections for 9V, GND, IN and OUT. Connect IN and OUT to the jacks
as shown. Connect all the GNDs together (twist them up and add a small amount of solder to tack
it). Connect the b lead to the 9V wire, same method. Plug in. Go!
It may sound cack, as you haven’t set the biasing of the transistors yet. For this you’ll need either a
digital multimeter (ideal) or your ears (hey, its your pedal and you know what sounds good).
Place the Negative DMM test probe on any GND point, place the other probe on the collector of Q1.
Adjust the bias preset until you get a reading of between 6.8 - 7.1v (or minus v if PNP). Sweet!
If it works, crack on and do your switch wiring. If not... aw man. At least you know the problem is with
the circuit. Find out why, get it working, THEN worry about the switch etc.
BATTERY
IN
OUT
Your nice, new circuit board
INCLUDING WIRED POTS!!!!
IN
9V GND
OUT
BATTERY
IN
OUT
Your nice, new circuit board
INCLUDING WIRED POTS!!!!
IN
-9V GND
OUT
PNP
NPN
Test the
board!
