The first module I decided to make (outside of a power supply) is a voltage controlled oscillator (VCO). After all, what’s the fun of a synthesizer if you can’t make noise?

Since this is all new to me, I based my design off of Moritz Klein’s analog VCO which features:

  • Coarse tuning
  • Fine tuning
  • Saw and pulse waves
  • Frequency modulation
  • Pulse width modulation

In addition to this, I also borrowed part of his wave folder design to also add a triangle wave output to the VCO.

🚧 Build Experience

It took two tries to design a functional control printed circuit board (PCB).

In the first one I designed I accidentally hooked up the wave folder to the pulse wave instead of the saw wave (inadvertently turning it into a volume control for the pulse wave), and I also inadvertently reversed the direction of all the knobs. I could cut traces and use jumper wire to fix the wave folder issue, but the knobs being reversed was the straw that broke the camels back.

I ended up redesigning and reordering the PCB to fix both of these issues.

Leave a Reply

Your email address will not be published. Required fields are marked *