Bypass switch pop

Started by NickP, March 15, 2015, 10:43:01 AM

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NickP

Hey all new here and new to pedal building. I have been working on a pedal and I can't seem to get rid of the sound of the bypass switch clicking through the amp. I have read everything I can find on the net and as far as I can tell tried them all. Pull down resisters, Several buffer ideas you name it. The noise only gets louder with the amps volume. I have stripped the pedal down to just the simple transistor based boost section. I feel it is the bounce in the switch itself because I even removed all components just ran the input and output jack through the switch and I still get it. I have tried different switches still there. It's hardly noticeable at low volumes but crank the amp and you know it's there. I'm buying the best switches available from my supplier. Below is the circuit cut down to the basic transistor pre-amp. I'm thinking changing the wiring of my switch but I can't see what I could do to it to make it better. Any help or ideas would be great I posted a pick of how it is wired at the moment. Thanks.



duck_arse

NickP, you have picked the world's most popular topic for yr first post. welcome to the forum.

we prefer circuit diagrams to wiring layouts, but we let the first offence go. so, find a resistor, anything from 1M up, and wire it from the SW1//C1 pad to the mid board pad w/ the two black ground wires. you now have an input pull-down resistor. does the popping remain?
You hold the small basket while I strain the gnat.

NickP

Thanks for replying. Sorry I will post circuit diagrams in the future. As far as the Pull-down resistor. I placed one as you suggest. I also tried that at the output as well. I tried 1meg, 1.5meg and 10meg resistors in those spots. I removed the entire circuit, so no caps to bleed or anything involved just ran the input jack to the switch and the output jack to the switch. No other components in the circuit and I still get the pop/click. I read someplace to also put a 10meg in series before the c1 cap. This was to solve the noise created by switch bounce. It killed the volume of the circuit of course but still got the click through the amp.

highwater

The ground wires in that drawing are daisy-chained to the max... is the actual circuit built that way?

If so, your input jack is connected directly to battery ground. That switching arrangement grounds the circuit-board's input to a different ground that is three wires and at-least five solder joints away from the ground at the input jack. The tiny resistances (less than what most multimeters can measure) in each of those connections add-up, and can easily cause all sorts of problems, including (I presume) popping.

Read-up on star grounding, and implement that. Basically, you want all the wires which go to ground to meet together at only one point, like a bunch of boats all tied to one pier. Your diagram shows all the boats tied randomly to each-other, and two of them are tied to two different piers.
"I had an unfortunate combination of a very high-end medium-size system, with a "low price" phono preamp (external; this was the decade when phono was obsolete)."
- PRR

antonis

The only thing left is to also ground the output...
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

NickP

Thanks guys I will try that. I never even considered all the grounds.