Darcy Neal will lead a workshop in Chicago on building your own synthesizer:

https://www.meetup.com/Solder-Stitch-And-Code/events/238959615/

We’ll learn about some of the building blocks of creating a synthesizer using the 4046 VCO and the classic 40106 CMOS ICs. The 4046 is a well documented and powerful IC that can be turned into a modular synth voice with just a few added components. Participants will learn to solder together their own prototyping PCB, build a circuit on a breadboard from a schematic, experiment with sensors, and learn the basics about how to produce custom circuit boards using design software like Kicad and Fritzing. No experience is necessary, but basic electronic knowledge or a strong interest in synths will be helpful.