# Pedal popping fixes??



## coachseeley (May 5, 2022)

Good evening,
I've used 3 different PCB manufacturers so far and I seem to encounter engagement popping with the majority of my PedalPCB builds (Modus Operandi, Transcendence, Arche, Shrapnel, Guardian, Magnetron, Spirit Box, Duocast, Ocelot, etc...).  The circuits sound fantastic once they're on, but engaging a pedal in the middle of a song, and hearing that pop, is a bit of a nuisance.
I searched through some of the posts and I see that a 100k resistor on the output is a common fix - as well as switching to tantalum on some of the electrolytic caps.
Question is, "where is the best place to place the 100k resistor from output to ground?"  Should I put it on the footswitch PCB?  Do I need to go directly from the output pad on the main board?
Thanks for any help you kind folks can offer?  I'm asking here because I'm not experiencing this issue with other PCB manufacturers.  On some of the problematic  builds, I've tried 3 different brands of 3PDT footswitch, soldered transistors instead of socketing them, put on some additional RPD, etc...  I'm wondering if I'm building all of these pedal incorrectly.  Thanks again.  (Pic is the latest build - Guardian)


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## Dr. Satan (May 6, 2022)

It depends on why it's popping, the most common reason for switch pop is the switch itself.  I recommend reading this- https://www.mrblackpedals.com/blogs/straight-jive/6629778-what-really-causes-switch-pop


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## Robert (May 6, 2022)

All of the projects you listed either already have a pulldown resistor on the PCB or have a volume pot on the output that does essentially the same thing so there's no need to add pulldown resistors.


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## phi1 (May 6, 2022)

Some but not all you listed have an electrolytic cap as the output cap. These can have a tendency to leak DC more than the pull down can neutralize, so I’d start with replacing those with film or MLCC. 1uF is plenty for an output cap in most cases.


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## phi1 (May 6, 2022)

For one that already uses a film output cap, you could try replacing the 3pdt stomp with one of the relay bypass modules to see if that makes a difference. 

As for the article, only the last diagram with the inline resistors is something pedalpcb kits don’t already accomplish. I haven’t seen it before but you could try it, by putting resistors instead of straight wire from the pcb to stomp switch on the input and output pins. I don’t think the article specified a value… just spitballing at say 1k. Would be interesting to see if it makes an improvement.


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## phi1 (May 6, 2022)

Oh one more thing, you can actually measure if you have a DC voltage sitting on the circuit input or output with a voltmeter. Could help in pinpointing the problem. Personally I haven’t had any issue with film or MLCC caps, just electrolytic.


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## Big Monk (May 6, 2022)

I see I’m going to have to ask the tough questions here. 

Your switches are poppin’, but are they breakin’?:


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## music6000 (May 6, 2022)

coachseeley said:


> Good evening,
> I've used 3 different PCB manufacturers so far and I seem to encounter engagement popping with the majority of my PedalPCB builds (Modus Operandi, Transcendence, Arche, Shrapnel, Guardian, Magnetron, Spirit Box, Duocast, Ocelot, etc...).  The circuits sound fantastic once they're on, but engaging a pedal in the middle of a song, and hearing that pop, is a bit of a nuisance.
> I searched through some of the posts and I see that a 100k resistor on the output is a common fix - as well as switching to tantalum on some of the electrolytic caps.
> Question is, "where is the best place to place the 100k resistor from output to ground?"  Should I put it on the footswitch PCB?  Do I need to go directly from the output pad on the main board?
> ...


I would start looking for bad solder joints on the pedals you mentioned as they all have been Built without your popping issue!
The footswitch will amplify a dodgy joint every time it is pressed!
or, you have cheap dodgy footswitch's ????


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## phi1 (May 6, 2022)

What do dodgy solder joints sound like? In the case of leaky E caps, some leak a lot, but not all, so it’s possible for one person to build without pop, and another to get pop, just based on components.


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## benny_profane (May 6, 2022)

What LED(s) / CLR(s) are you using?


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## music6000 (May 6, 2022)

I only use Nichicon & Rubycon & have never had an Issue!


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## coachseeley (May 6, 2022)

music6000 said:


> I would start looking for bad solder joints on the pedals you mentioned as they all have been Built without your popping issue!
> The footswitch will amplify a dodgy joint every time it is pressed!
> or, you have cheap dodgy footswitch's ????


Thank you. The first circuit I had trouble with was the Arche. I went through 3 different brands of footswitches and that didn’t fix anything.


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## coachseeley (May 6, 2022)

benny_profane said:


> What LED(s) / CLR(s) are you using?


All Tayda sourced. I usually prefer blue for the color. Does higher Vf come into play there?


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## coachseeley (May 6, 2022)

phi1 said:


> What do dodgy solder joints sound like? In the case of leaky E caps, some leak a lot, but not all, so it’s possible for one person to build without pop, and another to get pop, just based on components.


I wouldn’t say I’m a master builder, but I have several (40+ estimate) successful builds with PCB, strip and perf board.
Not saying it can’t be my error, just not my first rodeo.


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## coachseeley (May 6, 2022)

phi1 said:


> Oh one more thing, you can actually measure if you have a DC voltage sitting on the circuit input or output with a voltmeter. Could help in pinpointing the problem. Personally I haven’t had any issue with film or MLCC caps, just electrolytic.


Good stuff. Thank you


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## coachseeley (May 6, 2022)

phi1 said:


> Some but not all you listed have an electrolytic cap as the output cap. These can have a tendency to leak DC more than the pull down can neutralize, so I’d start with replacing those with film or MLCC. 1uF is plenty for an output cap in most cases.


Great info, thank you.


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## benny_profane (May 6, 2022)

coachseeley said:


> All Tayda sourced. I usually prefer blue for the color. Does higher Vf come into play there?


The LED can have an impact. The inrush current _could_ be an issue. Since you're having the issue with different types of circuits (i.e., gain, modulation, time), I would look to what is shared by all of them. The switch itself and the LED circuit jump out at me. Check the link below for some more information about LED popping.






						AMZ - LED Popping
					

How to stop the pops in audio from LED current surges when switched.




					www.muzique.com


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## coachseeley (May 6, 2022)

benny_profane said:


> The LED can have an impact. The inrush current _could_ be an issue. Since you're having the issue with different types of circuits (i.e., gain, modulation, time), I would look to what is shared by all of them. The switch itself and the LED circuit jump out at me. Check the link below for some more information about LED popping.
> 
> 
> 
> ...


great stuff!  I think I'll start here and simply swap LED colors.


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## Robert (May 6, 2022)

Just disconnect the LED temporarily, if the popping continues swapping the color won't help.


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## jeffwhitfield (May 6, 2022)

I’ve read that the last electrolytic capacitor in the circuit can cause issues…especially if it’s a cheap capacitor. They can hold a residual charge that can cause a pop when the switch is pressed. Need to look into this since I have quite a few that use tantalum instead of electrolytic.


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## coachseeley (May 5, 2022)

Good evening,
I've used 3 different PCB manufacturers so far and I seem to encounter engagement popping with the majority of my PedalPCB builds (Modus Operandi, Transcendence, Arche, Shrapnel, Guardian, Magnetron, Spirit Box, Duocast, Ocelot, etc...).  The circuits sound fantastic once they're on, but engaging a pedal in the middle of a song, and hearing that pop, is a bit of a nuisance.
I searched through some of the posts and I see that a 100k resistor on the output is a common fix - as well as switching to tantalum on some of the electrolytic caps.
Question is, "where is the best place to place the 100k resistor from output to ground?"  Should I put it on the footswitch PCB?  Do I need to go directly from the output pad on the main board?
Thanks for any help you kind folks can offer?  I'm asking here because I'm not experiencing this issue with other PCB manufacturers.  On some of the problematic  builds, I've tried 3 different brands of 3PDT footswitch, soldered transistors instead of socketing them, put on some additional RPD, etc...  I'm wondering if I'm building all of these pedal incorrectly.  Thanks again.  (Pic is the latest build - Guardian)


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## coachseeley (May 6, 2022)

jeffwhitfield said:


> I’ve read that the last electrolytic capacitor in the circuit can cause issues…especially if it’s a cheap capacitor. They can hold a residual charge that can cause a pop when the switch is pressed. Need to look into this since I have quite a few that use tantalum instead of electrolytic.


Definitely looking into that.  Thank you.


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## andare (May 6, 2022)

I found this 3pdt wiring scheme which claims to eliminate all pops.  Haven't tried it though. It requires removing any pulldown resistors.





Here's the full thread https://www.madbeanpedals.com/forum/index.php?topic=27743.0


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## giovanni (May 6, 2022)

Iirc it adds a 470K pull down resistor on the output?


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## jimilee (May 6, 2022)

Nobody has mentioned your amp, are you running through your amp? Does a buffered pedal before it fix it?


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## zgrav (May 6, 2022)

Popping switches are sometimes mysteries unto themselves.  My circulator pedal only stopped popping after I put in a soft relay switch.   For this question it is odd that the popping only appears with some PPCB boards, but it may have more to do with the parts sourced for them at the time.


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## mdc (May 6, 2022)

This worked for me when nothing else would. It's super simple...






						VoodooLabs Optical Bypass
					

Hi folks  This is a bit of a utility build report, but hopefully some others will find it useful? In any case, I've had a few builds lately with switch pop that wasn't cured through the usual methods. In digging around for a solution, I found the schematic for optocoupler-based bypass that...




					forum.pedalpcb.com


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## giovanni (May 6, 2022)

mdc said:


> This worked for me when nothing else would. It's super simple...
> 
> 
> 
> ...


I was looking for your post to share on this one!


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## coachseeley (May 6, 2022)

jimilee said:


> Nobody has mentioned your amp, are you running through your amp? Does a buffered pedal before it fix it?


I'm using a simple Hotone solid state job on my work bench.  It usually translates the same when using my HX Stomp or my little 6W 5F1 build I made.


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## coachseeley (May 6, 2022)

Robert said:


> Just disconnect the LED temporarily, if the popping continues swapping the color won't help.


When I took out the LED, the pop went away... therefore I proceeded to swap colors.  First Ultra bright blue, then ultra bright red, then red diffused.  They all popped the same.  I even tried the Muzique method mentioned by tying in a 390R resistor and a 33uF cap to ground.  It still pops...!!!!  Next step might be to swap out the 4u7 caps for better quality ones.


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## phi1 (May 6, 2022)

No need to change those two, C11 is responsible for blocking all the DC to the output. Strange that the RC filter on the led didn’t fix it even though removing the led did.


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## coachseeley (May 6, 2022)

phi1 said:


> No need to change those two, C11 is responsible for blocking all the DC to the output. Strange that the RC filter on the led didn’t fix it even though removing the led did.


That’s what I was thinking and saw that it was already film and 1uF.


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## Robert (May 6, 2022)

Try an ultra bright LED with a higher value current limiting resistor.


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## coachseeley (May 7, 2022)

mdc said:


> This worked for me when nothing else would. It's super simple...
> 
> 
> 
> ...


This is great!!
How would I use this with a PPCB board? They have the standard 4 pads at the bottom and the 2 pads for LED?


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## coachseeley (May 7, 2022)

Robert said:


> Try an ultra bright LED with a higher value current limiting resistor.


Awesome! Which draws less current, super bright or ultra bright? Are we talking doubling the value of CLR or even do something huge like 50k?


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## giovanni (May 7, 2022)

coachseeley said:


> Awesome! Which draws less current, super bright or ultra bright? Are we talking doubling the value of CLR or even do something huge like 50k?


It depends how bright you want it to be. 4.7K will blind you. Breadboard to find your favorite value. I would start from 10K.


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## andare (May 8, 2022)

giovanni said:


> Iirc it adds a 470K pull down resistor on the output?


Yes looks like that's what it does


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## music6000 (May 8, 2022)

Can you try this:
10K Resistor Output to Ground.


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## mdc (May 8, 2022)

coachseeley said:


> This is great!!
> How would I use this with a PPCB board? They have the standard 4 pads at the bottom and the 2 pads for LED?



I'd remove the LED from the PCB; wire power and ground from the DC jack to the PCB as usual; omit the LED connection to the footswitch from the PCB; then wire everything else as shown in the diagram. If you're not familiar with vero builds this would be a pretty easy one to start with.


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## coachseeley (May 8, 2022)

music6000 said:


> Can you try this:
> 10K Resistor Output to Ground.
> View attachment 26071


Will do.  When I first looked at the image on my phone I thought, dang... that's clean.  Seeing it on my computer... photoshop?


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## coachseeley (May 8, 2022)

coachseeley said:


> Will do.  When I first looked at the image on my phone I thought, dang... that's clean.  Seeing it on my computer... photoshop?


Much more tolerable... This pedal will be part of my base tone - and I think I can get away with the minimal pop.  Thank you.


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## coachseeley (May 5, 2022)

Good evening,
I've used 3 different PCB manufacturers so far and I seem to encounter engagement popping with the majority of my PedalPCB builds (Modus Operandi, Transcendence, Arche, Shrapnel, Guardian, Magnetron, Spirit Box, Duocast, Ocelot, etc...).  The circuits sound fantastic once they're on, but engaging a pedal in the middle of a song, and hearing that pop, is a bit of a nuisance.
I searched through some of the posts and I see that a 100k resistor on the output is a common fix - as well as switching to tantalum on some of the electrolytic caps.
Question is, "where is the best place to place the 100k resistor from output to ground?"  Should I put it on the footswitch PCB?  Do I need to go directly from the output pad on the main board?
Thanks for any help you kind folks can offer?  I'm asking here because I'm not experiencing this issue with other PCB manufacturers.  On some of the problematic  builds, I've tried 3 different brands of 3PDT footswitch, soldered transistors instead of socketing them, put on some additional RPD, etc...  I'm wondering if I'm building all of these pedal incorrectly.  Thanks again.  (Pic is the latest build - Guardian)


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## music6000 (May 8, 2022)

coachseeley said:


> Much more tolerable... This pedal will be part of my base tone - and I think I can get away with the minimal pop.  Thank you.


I'm Happy there was an improvement but I would still try a 1uf Tantalum Cap at C11!
Make sure you fit with correct Polarity!

I built this pedal with 9 & 18V Toggle switch power & it's Quiet when Footswitch is used!





						Guardian OD ( Peacekeeper )
					

A great sounding Low to Medium Drive pedal. I modded for 9v & 18v. I was hanging out for the 18v PCB Charge Pump & PedalPCB had a Proto type that would suit me as I had the optional Battery. You will see the PedalPCB Charge Pump released version has been revised & updated with reliefs to suit...



					forum.pedalpcb.com
				


I would look at using name brand like Nichicon or Rubycon or Worth Electrolytics in your builds!


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## coachseeley (May 11, 2022)

music6000 said:


> Can you try this:
> 10K Resistor Output to Ground.
> View attachment 26071


Just want to say thanks again for this recommendation.  This took care of the pop and the pedal is fully functional.  I also applied this method to other problematic "poppers" (PCB and Vero) - so they are sounding great as well.  Much appreciated.


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