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3 band parametric equalizer not equalizing

Started by joefox, October 03, 2022, 09:12:34 AM

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I purchased and built the following kit:
I can barely hear a sound difference operating the 9 eq knobs.
The only knob  that works is the global volume, making the pedal act as a booster.
I replaced all the chips with new ones, and checked the position and the values of all the components. I would appreciate if someone could give me some suggestions.
Kind Regards


Welcome to the forum, and congratulations on completing this build!

Some photos of your build would make it easier to help you.  While you're doing that, could you please use a meter to check the voltage from each IC pin to ground, and list them for us?  And here's the build doc for reference.


Thank you for your kind and quick reply. I think I solved the problem.
According to the wiring  instructions I downloaded from Musikding,
the 9v + and - had to be connected to the pins on the board named A and C.
This caused the power doubler chip to generate 16v instead of 18v. I moved the + to the pin named Vcc and the - to the pin named GND. Now I have 18v and
all works fine.
Thank you again.



Hi @joefox, or somebody else,
Would you mind to share the wiring instructions you mentioned for this project on Musikding? I looked all over the site and can't find it...