One of the most common questions I get is about how to wire the bypass switch. The diagram above shows one common method that can be used.
Note that the rectangular lugs of the foot switch go side-to-side. If you rotate the switch so that the long dimension of the metal lugs are vertical, it will not work properly.
On some effects projects, the output to the switch may be from a volume pot and not directly from the pcb. The mini-booster is a project that has a volume control on its output and the middle lug of the volume pot would go to the lug marked “from PCB Output”.
If I may be so bold, I prefer a method I acquired from DIYstompboxes. It sends the input of the effect to ground, which was a great solution for some popping I was getting from a couple effects I’d added true bypass to. It provides a convenient home for the LED resistor to boot. I drew a diagram located here: http://3.bp.blogspot.com/-9H8-agz_5c0/TtL1n1tpVgI/AAAAAAAAAXg/PtdhlzmL-RI/s1600/3pdt swtitch distortion%2B.jpg
Grounding the pcb input on bypass is a good technique to know, but only really necessary with high gain circuits that are not 100% stable. My relay bypass pcb grounds the input since it may be used with a variety of circuits.
The input grounding method is shown in the second drawing at http://www.muzique.com/schem/dpdt.gif
regards, Jack
Hi there, I’m really confussed about how to wire the in – out and the 9v jack to the PCB and the 3PDT, I am making the Tonepad’s Ibanez CP9 compressor. I’d really apreciate some kind of help with it, thanks!
Adrian, look at this image for wmore wiring info:
http://www.beavisaudio.com/techpages/StompboxWiring/StompboxWiring96.gif
regards, Jack
I need how to wire the in, out and the 9v jack to the PCB and the 3PDT. I am building the amz fx boost pedal. Thanks!
So would this wiring pcb work for true bypass loopers? Is it sufficient enough for that or should I be using a different wiring diagram?
Thanks,
Eli