It's his classic LFO (Cat Girl Synth 58).
First some unpopulated PCB pics.
And the reverse side.
Resistors, diodes, caps, beads. There are no hard to find parts.
The circuit uses a Schmitt trigger --> integrator ----> comparator.
Check out Ken's schematic.
The 1st section, the Schmitt trigger has a positive feedback applied to the non-inverting input.
In the integrator , the feedback resistance is replaced with a capacitor and finally the comparator
kicks in where we have no feedback loop. The comparator generates the square wave.
I've been getting a bit spoilt lately in building modules with surface mounted pots.
So decided to try adapting this.
It seems to work well.
Now it's time to make the faceplate.
Some useful links:
1. Adding a range switch - Muffs
3. Adding CV control - electro-music
4. Serge Audio & CV levels - muffs
5. Ken's own site - CGS
6. Video - youtube