finished my first project without asking for any help aside from verifying the placement of some added decoupling caps and it actually worked first try! i built two of thee at the same time so thats amazzing news. also made two MS20 filters and a wav trigger. PWM adjust doesnt seem to do a whole lot but it does something. might just need a little fiddling. everything else works as expected
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I gotta have one of those vcos. I need to get a scope so I can do it.
honestly sounds pretty good even before tweaking. im having some weird tuning issues now but its a cold joint or something somewhere first it was too low now its way too high and when i jiggle the board it does…stuff so at least its not the transistors. it stays pretty locked to what ever pitch range it jiggles itself to. i got the pwm range fixed for the square wave too
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Could it be a bad pot?
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yea i think thats exactly what it is maybe a piece of metal got into it or something its reading over 100K resistance from both legs at every setting. took me an hour of testing to come to your first guess haha i did a cont. test from the pot cast to the legs and it wasnt triggering but it was showing a reading so i started by taking them off the panel and one reads true and the other is maxxed out. i hope thats all it is. taking a little break lol
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Right on! I’ve had so many bad potentiometers. All types of circuits too. That glitchy behavior that seems to happen anytime you touch anything on the board…usually ends up being a bad pot for me. Lol.
It’s odd because It worked perfectly at first then went weird. Any pot with no stamps on it is sus I’ve had a couple spark up on my from loose windings hitting the terminals…there’s someone on eBay selling ten packs with knobs for 5-10$ they are a much higher tier than what I was getting
yep was just the pot! its back to going out of audible range in both directions. i got my polystyrene caps yesterday im going to finish up these filters and see how it sounds thru some MS20s. you could always use a scope in a daw or something to tune yours i just got that little red kit one cuz it looks cool
all the waves are about perfect at half position on the trimmers the sine roundness needed increased slightly but honestly sounded less interesting with the lower volume and harmonics. im probably just going to set them all by ear anyways
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This is encouraging. Lol. I’m probably gonna order a scope soon anyways. I’ll have to build another case too. 
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ive been getting quarter sheets of presanded plywood for 18$ they would normally cut them for you as well but the saws been busted at my home depot location.i used to install signs so i have a lot of aluminum laying around. i built this one 100% with a dewalt cordless sawsall and its not exactly all straight but i ordered a corded jigsaw for the next round
have you made the ms20 filter yet? i made two and they sound great but they are picking up signal from the osc somehow and self oscillating. do you think jumping power from the osc board to the filter boards could be the cause?
I have made 2 ms20 filters. One is from Juanito Moore on his site Modular for the Masses. It it pretty much exactly like Rene Schmitz circuit which is the other one I built. I think Sam’s Circuit is pretty much the same as Rene’s circuit as well. It could be tied to the power jump. Do you have decoupling capacitors between your positive and ground, and negative and ground rails on the strip boards? I never had problems with it self oscillating unwanted. You can adjust the value of the resistor going to ground in the feedback loop. I forget which way you would go to decrease the effect, though. You could just replace it with a potentiometer set up as a variable resistor. Then adjust it as needed. Here is how Juanito Moore does it. Note the “resonance trim”
Also I have Incorporated a attenuator at the input of each one of my builds as they would not work properly without. Some signals are too high in amplitude. Also, it’s a good idea to have the decoupling caps if you don’t already even if it doesn’t fix the problem.
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i have two filters they are both picking up the VCO i tried adding dedicated power neg and ground they sound cleaner but still picking up the signal and oscillating
i have pots on the inputs and also the cv inputs
i have caps near the chips but not on the power input. maybe two 10uf on the power as it comes in?
also the pitch changes as you attenuate the signal into my six channel attenuator like some how the flow through it is changing the freq
how the heck can you build from that i cant even tell which place each chip would go
i bet its the poly styrene caps i just guess what direction the 1nf went in and put the stipe towards the neg input