Chop Shop Calibration 12/15/22

[abelovesfun]

Built a chop shop. It passes signal and all controls seem to work. I just am unsure on calibration as the documentation has nothing there: https://docs.pedalpcb.com/project/ChopShop-PedalPCB.pdf

Right now I have all pots at 100% but my max DC measurements on the test points is 2.5V. Should all pots be at 100%. I used a 2n2222a so I put it backwards, and the J201s are from a trusted batch that I use to make triangle > sine shapers all day.

 

[BuddytheReow]

Sometimes it’s best to tune your FETs by ear rather than a specific voltage. Adjust the first trim pot until it sounds best to you, then do the second one. Then go back to the first one and fine tune it. Everything should “snap” into place

 

[mdc]

I believe the spec is ~6V.

 

[Ale_jellybelly]

Sag pot should be all the way counterclockwise, so at 0%
And from what I read both JFETS should be biased around 6v, I biased mine at 6.5v

 

[abelovesfun]

Thank you. At 0% Sag I can get one down to 7V. The other one can go below that but i matched it to 7V. the Sag range is quite strange.