BSIAB audible footswitch POP!!

[SpikeVelvet]

What can be done to silence the audible footswitch pop? I built a BSIAB from the GGG kit and I was under the impression that R1 was the pull down resistor and that it was there to keep the footswitch noise under control. Is there anything else I can do?

[deadastronaut]

try input and output ground in bypass wiring on your 3pdt.

https://www.diystompboxes.com/smfforum/index.php?topic=104109.msg931319#msg931319

[antonis]

And what about LED-pop, all time lazy Rob..?? 

[deadastronaut]

indeed...that as well...

[SpikeVelvet]

Thanks for the help!! I wired that up and it improved it. It's not silent but it's greatly reduced.

[SpikeVelvet]

Quick question....would a bigger CLR or a bigger capacitor reduce the pop even more? The BSIAB uses a 1k CLR and I used a 10uF cap to ground. If I go to 4k7 and 47uF would that reduce the pop even more?

Thanks

[MrStab]

yknow what i find helps? a really bright LED - 3,000mcd or so - and a 10k+ resistor. then you're only dealing with less than 1mA of stray current, and you're wasting less power in the process.

[SpikeVelvet]

Is there some math behind this you could reveal?

[MrStab]

just Ohm's Law. 9V / 10,000 ohm = 0.0009A, or 900 microamps. maybe try switching the 4k7 in Antonis' suggestion to 10k? it won't completely eliminate pop, but it'll help. 4k7 is fairly high already, though.

you can go higher than 10k, and you can get brighter LEDs. ultra-brightness is a luxury of the modern age.

does the pop still happen if you disconnect the LED altogether...? because the high-gain BSIAB circuit or (rarely) switch microphonics could be contributing to the pop.

[SpikeVelvet]

Thanks MrStab,

Currently there is 1k in the circuit, which GGG uses as the default. Swapping a 4k7 or a 10k is an easy fix. I'll try that.

http://www.generalguitargadgets.com/pdf/ggg_bsiab2_sc.pdf

[MrStab]

no problem! change the LED too, though, if it's not super or ultra-bright. just as an example, here's what i usually use with 10k's:

https://www.rapidonline.com/kingbright-l-7113src-j4-5mm-super-bright-red-led-3500mcd-55-9212

[antonis]

Well said above  but are we sure popping is due to LED activation..??
(meaning, are everything OK with LED not powered..??)

<Is there some math behind this you could reveal?>

Additional to what Mr. Stab well said..
4k7 resistor & 10μF capacitor form a low pass filter of about 3.4Hz cut-off frequency with also a time delay of about 200ms (for 4.5 X RC) - you might (or might not..) notice that delay on LED activation.. 

[Ice-9]

As a test to find the cause of the pop you can remove the LED altogether, this will tell you if the pop is coming from the LED or other source.

[SpikeVelvet]

Thanks Ice9 I will try that because I tried a 10k and it did not improve the popping

[willienillie]

I recently experienced a very noticable increase in switch popping with ALL of my pedals.  I measured DC across the input of my amp, after it was on for a while it got as high as 80mV.  There was a nearly new JJ 12AX7 in V1.  I swapped in an old Sylvania and the problem was cured.

[SpikeVelvet]

Thanks Willienillie,

I'm not experiencing a pop from my other pedals so I will keep that in mind. My other DIY pedal is a BYOC Silver Pony and it has an audible acoustic "click" sound you can hear in the room but NOT in the signal path. The BSIAB definitely produces a POP that is in the signal path.