Chauffer overdrive

Haz

Active member
Hello!
Got this together on pedalpcb testbench. I hardly get more volume than unity and I get 6k squeel which is same volume as output. All pots are working I am getting the sound.
I tried to swap all the chips but that didn't remove the squeel.
Any help?

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If you have some TL072s on hand. Try replacing the 4558s. The JFET opamps seem to be more stable. If that works, you can debug the 4558s. You could use your scope and see where the oscillation is occurring.
 
Hello, thank you for reply. I tried exchanging for 4 TL072CP I had on hand for the first 4 slots. I get less volume but noise is still the same. On the scope I see it on charge pump IC but trying multiple of theese doesn't remove the oscillation
On adding more volume I get this (audio)
1651343883129.png
 
Ok I think I've solved this. It's ofcourse the IC5. Now pedal seems to work fine with TL072!
Actually 6k squeel came from IC. Other glitches from IC5.
 
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