Eliminate Popping using Stomp Switch

[kreiff]

Hey All,

After getting the “Realtime Adjustment of Sampling Rate and Bit Resolution” example working and running various audio through it I realized that it makes for a pretty awesome 8-but fuzz effect. I decided to desolder the bypass switch, the two trim pots (pre-gain, Volume), and the 3.5mm jacks and replace them with a 3pdt footswitch, two regular pots, and 1/4″ jacks.

The effect works great! You can get very cool 8-bit video game sounds as well as very gnarly gated fuzz sounds.

The only issue I’ve got now is that when turning the effect on / off with the footswitch I get a “pop” sound. It occurs both when the effect is turned on and off, but is more pronounced when the effect is turned off.

I’ve read some methods for eliminating popping for DIY guitar effects – but the Nootropic shield isn’t really wired the same way as a traditional guitar effect which has an onboard bypass.

Any ideas for getting silent switching with the Nootropic shield?

Here is my wiring diagram below – Maybe I’ve also wired something wrong? Any feedback welcome!

[kreiff]

On additional note! I ended up having to add jumpers where the 3.5mm jacks were to get the signal to pass through the bypass switch. You can see in the wiring diagram where I’ve added the yellow jumpers between the pads – this is how I soldered it – not sure if that might have an effect?

It seemed that the two jacks that came with the kit were connected between those 2 pads. (I checked with my multimeter at least and got a continuity *beep*).

[Michael]

Hey kreiff,

I’m not really an expert on guitar pedals, but I have read that popping sounds can be eliminated by connecting a large resistor (like 1M) between the audio signal and ground. This gives the circuit a path to bleed off the voltage when you turn it on/off.

http://www.tdpri.com/threads/loud-popping-from-true-bypass-pedals-why.220568/

Google and you can find some references to this solution. It won’t hurt to connect a large resistor to ground.

[Michael]

Hey kreiff,

I’m not really an expert on guitar pedals, but I have read that popping sounds can be eliminated by connecting a large resistor (like 1M) between the audio signal and ground. This gives the circuit a path to bleed off the voltage when you turn it on/off.

http://www.tdpri.com/threads/loud-popping-from-true-bypass-pedals-why.220568/

Google and you can find some references to this solution. It won’t hurt to connect a large resistor to ground.

[kreiff]

Thanks, Michael! I’ll give that a try!

[Author]

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