# power supply noise filtering constrictor - compulator clone



## c.est.baastien (May 10, 2019)

Hi
I am building Constrictor project and after solving ground issue, as reported here : https://forum.pedalpcb.com/threads/weird-issue-with-constrictor-demeter-compulator.292/
it finally works. But...

But I am facing now a noise filtering issue :
- When pedal engaged at low settings (i.e. no extreme settings) + battery powered I've got a kind of shower noise / white noise, much more than that we can normally expect from compressor.
- Same settings this time with power supply (Zoom intended for audio/pedal powering), it brings a huge wow. Something more bassy than classic 60 cycle hum.
- And in the end, powering the pedal with my Cioks Big John power supply : very small amount of noise, only noticeable at extreme settings.

Well since this pedal is not intended to be used on my main board, I cannot power it with my Cioks power supply unit, I cannot live with that.
So I need to find the proper filtering for it. I have build other project that I will put in the same box with Constrictor comp, I do not have noise with them, using both same power supply and battery.

People here do you have faced this kind of issue and how do you fixed it ? Do you have some clues or indications in order to tame / filter that noise ?
Cheers


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## c.est.baastien (May 16, 2019)

Well
One improvement : having the LED soldered helps to tame the white noise WHILE POWERING WITH BATTERY the pedal.

Another test I made : I have powered the constrictor with an «old» linear transformer. It brings some noise, thing that my Cioks Big John don't.


Nobody has clue / info / advice to share ?
Cheers


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## Bonair (May 17, 2019)

Perhaps swapping out the filtering cap just to rule that out? Also you could try moving input/output/9v wires to be sure they aren’t running on top of or alongside each other, if they need to cross try and make them pass each other perpendicularly. Or once you’re done with soldering everything that should soldered you might try boxing it as is, since many times the enclosure itself will block out noise, especially if you’re testing the circuit out in the open anywhere near a computer monitor/laptop or flourecent lighting.


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## c.est.baastien (May 17, 2019)

Bonair said:


> Perhaps swapping out the filtering cap just to rule that out?


Thank you your answer. What cap value do you encourage me to test ? It is currently 47u



> Also you could try moving input/output/9v wires to be sure they aren’t running on top of or alongside each other, if they need to cross try and make them pass each other perpendicularly.


Ok, understood thanks. Tested out of the box with circuits and cables in «star shape» disposition. So the issue doesn't came from here.



> Or once you’re done with soldering everything that should soldered you might try boxing it as is, since many times the enclosure itself will block out noise, especially if you’re testing the circuit out in the open anywhere near a computer monitor/laptop or flourecent lighting.


Right about external electronic noise pollution, but not incriminated here.


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## zgrav (May 17, 2019)

You can replace the filter cap with the same value, or one a bit larger.  you could also make sure the one there is oriented correctly and retouch the solder points on it to make sure it is actually in the circuit and working.


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