footswitch pop

[davohilts]

Hello All,
I've just finished my first pedal and it works great. It is an engineer's thumb with a JMK circuit board.
http://jmkpcbs.com/wp-content/uploads/2014/08/Engineers-Thumb.pdf
I have only one issue and I'm unsure how to address it and that is when the footswitch is engaged it pops. I assume I need to add a small cap or resistor to stop this but I'm not sure where to put it.
The design uses a true bypass footswitch that has 9 pins in 3 rows of three. The input and output, effect in and out, led, and ground are tied to the footswitch.  Would I connect a cap across ground and effect out pins to stop the pop?
Any help would be greatly appreciated.
Dave

[Mark Hammer]

The Thumb itself shouldn't pop.  Could be a case of pedal ventriloquism.  Are you using the thumb in conjunction with another pedal that uses electronicswitching, like a Boss pedal?

[davohilts]

thanks for the help. no the pedal is on its own for my use but when it popped a friend was trying it out on his pedal board but they all had regular switches. I don't have the pedal to test right now but will try it on its own when I can. Would it help to try and isolate the switch from the pedal enclosure?
Dave

[Agung Kurniawan]

The right pull-down resistor value will reduce the pop. Or if you want you can use kind of a Zoom Trimetal switch.
Or maybe the pop come from the LED.

[GibsonGM]

Or maybe the pop come from the LED.

Might help (?) http://www.muzique.com/lab/led.htm

[Mark Hammer]

The LED is also a good suggestion for where to look.
These days, we have the luxury of high-efficiency LEDs that can glow bright on negligible amounts of current, such that when they get turned on, they don't draw enough to make objectionable pops.

Something rated at 8,000mcd or more can have a current-limiting resistor of 10k-12k or more and still be quite visible, reducing the current draw.

[Agung Kurniawan]

Yep, im using trimetal switching without the Jfet. So the input buffer would be the signal splitter. One come to input effect, one to the output jack. Using a dpdt switch, one side for the signal switch, the other for the LED switch. No Pop come when I step the switch

[davohilts]

The LED may be the culprit! I'll try a 10K dropping resistor and see what happens!
Thanks

[Agung Kurniawan]

There is a good article about LED pop and how to remove them on AMZ

[davohilts]

Thanks for the tip. What is AMZ?

[rutabaga bob]

Go to the top of the page and look at the links...AMPAGE  GEOFEX  AMZ

[amz-fx]

6 Reason Pedals Pop When Switched: http://www.muzique.com/lab/pop.htm

If you play at a really loud stage volume, most pedals are going to pop except those with specially designed silent switching, such as Boss.

regards, Jack