I didn’t find it too hard after a few watches of Sam’s vid.
Have the test point voltage at 4.0v then work on getting the octave switch to stay in the same place when switching but not necessarily on tune and finally use the center to bring it in tune.
There are some half way good tuners on Ur phone that display in cents, better than the 3 LEDs on the 1222 panel lol
Here’s a fun one. I haven’t changed anything in my case, but one of my oscillators all of a sudden is WAY off in both pitch and tracking. It’s been working well for years (even on the previous mediocre power supply). I need to break out the multimeter and get to troubleshooting, but I’m hoping maybe one of y’all might have an insight that gives me a head start. Any ideas are appreciate. Thanks!
If your R42 is a 220R, your LM4040 may have given up…
It was abused (run way out of specs) all these years and now it’s gone…
Should the PWM controls effect the saw tooth at all?
It’ll affect the frequency of all the waveforms, unless you do something to address that. There’s discussions on this forum about it. Basically you may be able to stop that with a suitable resistor, though I think a more reliable answer is to design it with a regulated -9 V supply instead of using the -12 V. It shouldn’t affect the shape or amplitude of any of the other waveforms though.
It’ll affect the frequency of all the waveforms, unless you do something to address that. There’s discussions on this forum about it.
Ahhhh! This makes a lot of sense. I have read the discussions but never actually made the connection before now. I suppose a good solution is the old patient/Doctor exchange… “It hurts when I do this” “So dont do that”
I have hooked my VCO up alongside a Midi-CV and my Midi keyboard, when pressing the keyboard the note is continous and doesn’t turn off when the key is unpressed. How do I make it so that the note is only triggered when the key is pressed down?
That’s how VCO’s work, they just create a continuous tone, if you want it to turn on and off you need to pass it through a VCA controlled by an Envelope Generator and that should be triggered by your MIDI to CV gate output.
Welcome to the world of modular synth.
Thank you!
Which of sams modules will help me with this? I have a VCA mixer but I can’t imagine that will help me?
A VCA will help if it has a CV input to control the level. Then you need an envelope generator to create the CV to open the VCA when you press a key.
Maybe some help here 
I found VCV Rack very useful in planning projects as I get a good understanding of what each module does and how they interact; you can even combine your VCV Rack with whatever you build.
Crack on!
[side note]
After all this time, years of reading, posting and mayhaps confusing, Farabide, that’s me,
has just earned
his
First Link Badge!!
I don’t know what to say, this is so unexpected!
My thanks of course to Discourse, Sam and our very own moderators @Caustic and everyone here who makes this community that safe somewhere I can post links for Badges.
Thanks again!
I made my own version of the tuner code: GitHub - Krakenpine/Modular-oscillator-tuner: Somewhat more stable version of tuner for LMNC oscillator
Might be worse than the Tune-O-Matic that is mentioned in the project page. But I’m bad at reading other peoples code and wanted a simple way to set what frequencies are considered to be in tune and what are the ranges of notes.
Having some troubles with this one today. Built another 2 but one wont track through the octaves properly. One works like the dream but the other is fighting me. I re picked all the resistors and ensured they were all identical to one another for the octave switch, tried changing out the switch and wiring for the exact same issue.
Each time ive tried to fix it it has also not tracked properly in the exact same amount. Could this be my chip at fault?
Ive done all the other calibration but this is the one im stuck on. No matter how much I fiddle with the tracking pot its always off by a considerable margin
Any help would be cool
Thanks <3
Swap the chips between modules to test your chip.
If the fault stays with the board then start looking at bad connections, broken traces especially around the scaling and CV input.
First step should be to check where the problem is originating.
Is the octave switch producing exact multiples of 1 V at each setting? Check at the switch output with a multimeter.
If it isn’t then either there’s something wrong with the resistances on the switch or with the reference voltage supplying the switch.
If it is, look into the chip and the components/connections associated with CV and scaling.
Solved it. But its one of those where I have no idea how. Got ahead of myselft and tried many different things at once. They live to fight another day. Thank you all
I have been looking at the Arduino code for the tuner, and I am a bit baffled. Not by the code itself - I’m a professional software engineer.
It’s the code that determines what note it is. It checks whether the frequency lies between certain values to see if it’s a C, C#, D etc.
What I don’t get is that concert pitch A (the A above middle C) is standardised (in most cases) on 440Hz.
However, where the code checks for values around 440, it’s saying it’s an F. All the frequencies seem right relative to each other, but they don’t align with the standard frequencies of the chromatic scale.
Can anyone explain why there is this offset?