I'm building a wah pedal using the layout from this site but am having trouble getting it to work. No matter what way I try to wire it, I get no signal when it's switched on. I built an audio probe but i get noise at different volumes depending on where i touch so i'm confused on the audio path from input jack to out put jack. I'm still pretty new to this so I'm wondering if someone could help me figure it out. I ordered most of the parts from Stuart and mouser. I made a PCB (from here), populated the board. I believe I have pretty good solder joints (i see no obvious breaks or cold solders). I measured the caps and resistors and everythiong looks good. I even measured for an open on the inductor and that looks good also. I can only guess that something is wired wrong. Is there a way to bypass the switch so it's always on just so i can see if the ciruict works?
Maybe someone could be so kind as to outline the audio path so I know where to probe and what to look for.
Did you build the wah with an output buffer? If you did, here's a short write up that I did that outlines how the wah pedal output buffer should be wired into the circuit:
The output buffer should be wired with pads 1 and/or 5 grounded to either the input or output jack...this makes sure that the circuit has a solid ground. Not having a good ground can cause some strange things to happen, so I would connect the ground from the buffer board to the ground of which ever jack has a ground wire going to the main wah circuit board.
Pad 2 is the input of the buffer circuit, which is connected to the output of the wah circuit. The ouput of the wah circuit is from lug 3 of the wah pot. The wire that goes from lug 3 of the wah pot to one of the lower legs of the switch is the output wire, and it needs to be removed and a new, longer length of wire needs to go from the third lug of the wah pot to the input of the buffer board.
Pad 3 is where you connect +9VDC from the main wah circuit board.
Pad 4 is the output of the buffer circuit. The output goes to the same lug on the bypass switch where the short wire from wah pot 3 (which was removed and replaced with a wire going to pad 2 of the buffer circuit board) was connected before.
All three leads of the trimpot should be connected to a part of the buffer circuit board. The trimpot pads are layed out so that it will accept three or four different types of trimpots with different lead arrangements. You have to pick the solder pads that match the lead type of your trimpot and drill out those holes. One of the "outside" legs should be soldered to the pad that's connected to the output side of the 1uF capacitor, which is the side opposite the "source" of the JFET. The center lead should be connected to one of the pads that's also connected to pad 4 (the output of the buffer circuit). The remaining "outside" lead of the trimpot should be soldered to the ground solder pad for the trimpot, which is also connected to pads 1 and 5 on the board (the two grounding pads).
