Problems with the stripboard Lp vcf layout



Ive double triple checked. What I don’t understand is how the cutoff works in the circuit. Is it fully open when no voltage is applied or fully closed with voltage applied. I also don’t really get why the volume knobs just act like a switch essentially. Ive wired them in in the same way the attennuators are but it just is either all or nothing. I must have super crap luck with strip-board as it never seems to work lol. All the pcb’s have been fine aside a few crap jst connectors

without any external voltage you should have (in LowPass mode) the sound muted with the Cut Off pot completely closed on the left, and completely open on the right the sound should pass

I have the same issue with the CV level pot, keep meaning to try with a different taper pot.

Have you got a multimeter? If so, take a voltage reading at each pin and post here. It’s hard to troubleshoot from the info given.

Are your transistors and IC chips in sockets? If so, worth swapping them out. Where did you get the lm13700 from? Make sure it’s a good supplier.

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Yeah, so currently for me with no external voltage sound passes no matter where I have the cutoff set, I even double checked on highpass which makes it go completely silent as the cutoff seems stuck open. Which probably explains why the resonance only makes the leds light but not affect the sound…maybe…

Yeah ill try and take measurements, I just have very little of my own time at home atm. My LM13700 is in a socket. I got them from tayda. I also used the same batch in the funky filter and that seems to work fine I think

in HP mode, it’s the opposite: on the left it is completely open, and on the right completely (near) closed

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