Switch Pop on a King of Tone clone

[bikersluggo]

Hi all - new member here.  I started building effects just this year and I have 10-12 under my belt, but I still feel like I have a lot to learn. 

Anyway, I just finished a King of Tone clone built on a Cerulean (Blues Breaker clone) PCB board from Aion Electronics.  This board has a pull down resistor and I used a 2.2 M ohm value.  I'm getting some switch pop despite having the RPD.  I pulled the resistor out and checked it and it measure fine at 2.2M.  I've searched a little on this subject and I've read that the value of the pull down resistor doesn't matter, but is this really true?  If I'm still getting some pop with a 2.2M, should I try a larger (10M) or smaller (1M) resistor in it's place? 

I also read that it could be the LED.  Would the color of the LED make a difference? I doubt it would, but I've heard that when LED's are used as clipping diodes the color makes a difference so...  I saw something about adding another resistor and capacitor to the LED part of the circuit but I'm not sure what the best way to do this would be and what values to use or how to even isolate the cause of the pop to the LED.

Thanks for your help,
Bikersluggo

[rousejeremy]

Does the switch still pop after you turn it off and on a few times?

LED colour doesn't matter.

[dwmorrin]

Recently there was a pretty good pop thread here: http://www.diystompboxes.com/smfforum/index.php?topic=105580.msg951456#msg951456

Ultimately, the poster fixed the problem by switching to this switch wiring: http://www.madbeanpedals.com/tutorials/downloads/StandardWiring_MBP.pdf

With that wiring, the input to the distortion is switched to ground when bypassed.  May or may not help you in this case.

[bikersluggo]

The pop does not diminish if I switch it on and off several times in a row. 

I thought about trying a different switch wiring scheme.  I'll read through the other thread.  Thanks for the heads up.

[jimilee]

May sound silly, but have you tried different amps or guitars?

[kaycee]

Try checking for a loose ground connection, reflow those joints. I've had that cause popping before, and as mentioned, some switches aren't that great and can cause this too.

[bikersluggo]

I tried the MadBean switch scheme.  It didn't help.  I did rewire the same switch, so it could be this one specific switch maybe?  One thing I did read in the other thread that was referenced was that other pedals in the chain could cause it because of buffering.  I do have some Boss (buffered) pedals both before and after this one, so I'll play around with that next.

[rousejeremy]

This may be a stupid question, but are you talking about a popping sound coming through the amp when engaging the effect or the actual switch making a loud noise? Only asking because I had someone ask me about his POG making a loud popping sound and after explaining pulldown resistors I realized he was talking about how loud the actual switch was.

[nate77]

I've built a few of these KOT clones from Aion and I've had the same issue. I stay in touch with Kevin (who is aion electronics) and ive come to believe that it may be the curciut itself although I'm not sure why. I've altered the value of the pull down resistor from 1m all the way to 10m.l and no luck. I've also built 2 1:1 vero KOT clones and another from a PCB from a very reputable DIY community staple and same thing, pop when engaging effect. I've campaired the BB PCB from aion to the schematic for the KOT (or more accurately the prince of tone) and it is right on so I'm also baffled. I know this doesn't actually help, but it is common. Does anyone know if there is anything that could be holding a charge each time it's engaged? Like states earlier, it doesn't disparate regardless of how often it's engaged consecutively.

[bikersluggo]

Thanks for the reply, Nate.  It's good to know I'm not the only one.  It's a shame because I love the sound of this thing when it's on.  It's my fav OD.  So what does Kevin say about it?
I did pull the pedal off of my board and test it alone (still pops) and with a buffered pedal in front of it (a little better) and with a buffered pedal behind it (a little worse). 

I was thinking about trying different pull down resitor values, but I'll hold off until someone has a better idea.