DIY AB Switch for single input stereo pedals ground loop and pop concerns

Started by toostomped, September 03, 2017, 10:38:58 AM

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toostomped

Hi all -

I am hoping for some advice before I plug in the soldering iron.

Here is my pedal purpose description:
I have 2 stereo pedals that only have 1 input and would like to toggle between them with a stomp switch so they would connect into my boss dd-7 stereo delay. No leds needed.
My attached diagram shows what I am hoping to accomplish, but I am not sure if I am going to run into "thump" or "pop" issues when switching, or if I need to address any ground loop issues.

I thank you in advance for any help you may be able to provide.




PRR

Welcome.

Looks OK to me. Let's see if anybody (dis)agrees before you hot-up that iron.

BTW FYI-- that is a triple pole double throw switch.
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toostomped

Thanks much for your reply. You are correct... I meant 3pdt (just fixed the diagram). I was am mostly concerned about wiring all the ground terminals together and creating ground loop hum (although I think that may only apply to the power going to the pedals being daisy chained). I will see if anyone else chimes in before the tin gets melting. Thanks again. Enjoy the rest of the holiday weekend!

karis12

You might need pull-down resistors for the Guitar out A and B jacks - I built a similar (mono) switcher in the past, and there was a popping sound when I stepped on the switch. You can solder 10Meg resistors across the tip and sleeve lugs to prevent this.

If you have access to a 4PDT, you can eliminate the need for the resistors by using the extra pole to connect one Out to ground when the other makes contact with the Guitar In.

toostomped

Thanks for the "pop" workarounds. I have created a 4PDT diagram that I think illustrates your suggestion. I have used the 4th pole to alternately connect the two guitar outs to ground. Just wanted to make sure I wasn't supposed to deal with the "left" and "right" outs instead. Thanks again. Best regards.

PS - If anyone else would like to comment, I am more than happy to welcome more cooks into the kitchen.