I have built a few of these OD's and always had great luck with them , but i have one that has a very strange noise when the gain pot is tuned all the way down to zero , it sounds like someone tuning in an old ham radio etc . You get alot of hiss , fuzz , and some crackling while the pot is in motion . But if you turn the gain pot up just slightly to about 15 - 20 % , the noise goes away ?
This noise happens with effected circuit , and bypass too .
I have replaced the gain pot with a new one 100KB dual , and increase the R28 value to 150R , replaced the charge pump chip from a TC1044SCPA to a 7660SCPA , and the TLC274 chip with another new one .
The noise is still there .
Thanks for any help or ideas !!
Bump ...
necro bump.
i'm having the exact same issue.
D9E diodes, TL274 op amp, 1044scpa pump.