4-CD40106 Osc with CV

[Vampyre]

I seem to have an obsession (maybe a bit harsh) with the CD40106 IC. It also might be due to the fact that I have a large amount of them so I want to use them in something. Anywho I was trolling the interweb for 40106 circuits and found a couple that showed CV IN. Now that is something that I haven’t tried. The first circuit (which I have since found on this forum) used a 1N4148 Diode at the input. Well I tried that and couldn’t get it working. Move on… The second circuit used a 10k resistor at the gate input for CV IN. So I breadboarded the circuit and holy crap it works. I then added some switches and some 100k resistors so I could switch between single Osc out and mixed osc out. I havent moved it to a strip board yet but that is the next stage.

[Dud]

Maybe you seen it but … here’s the @moritzklein VCO with CD40106 with 1V/oct (video part 1/2 & 3)

DIY Synth (electronic video for beginners) - Moritz Klein

I just watch this video, and I found it interesting and simple [DIY VCO Part 1: The analog oscillator core anyone can build] DIY SYNTH VCO Part 1: How to build an analog oscillator core from scratch In this series, I’m taking a detailed look at how to build an analog VCO from scratch, using just a handful of cheap components. It’s the basis for any synthesizer. To keep it as beginner-friendly as possible, I’m explaining what all the components do in detail. This first part deals…

[analogoutput]

And one from Synthfox:

https://sfcs.neocities.org/module/SFP21/

Here’s the core of it:

for 1 V/oct (it could be made more accurate with a few more components)

It has a diode instead of a resistor in the feedback path, so the “output” signal is just a series of narrow pulses, but the voltage on the capacitor is a ramp wave, and then there are shaping circuits to make pulse and triangle.