CD40106 Oscillator Bank

This was the first analog synth module I’ve built. It works on +9V power supplies. It’s also the first synth module I’ve demoed on Youtube.

It contains six independent square-wave (or triangle if you include it in your build) oscillators. The range of each oscillator can be controlled by changing two components, a capacitor and a potentiometer. This is explained in the schematics section along with combinations I’ve tried.

The oscillators can be chained to produce interesting textures and rhythms. The SYNC_OUT of one oscillator can be connected to the SYNC_IN of another. I demonstrate this in my breadboard demo:

Here’s the module after I’ve built it on perfboard and mounted it to an acrylic panel:

This build is heavily based on on Kristian Blåsol’s oscillator bank. You can watch his video here. This series is very informative:

Schematics

The CD40106 chip contains six available Schmitt-trigger inverters. This means we can repeat this circuit six times with a single chip. The triangle output section is also optional. (I did not include it in my final build)

Values of RV1 and CP1 can be adjusted depending on the desired frequency range. Don’t be afraid to experiment. I even replaced RV1 with a photoresistor in my breadboard demo.

Let me know if you’ve built it! Tag me on IG @benjiaomodular.