Kassutronics variable shape LFO

This is a dual LFO synth module in Kosmo format, based on a Kassutronics design. There are three outputs for each LFO. Depending on the shape pot setting these provide ramp, asymmetric triangle, symmetric triangle, or sawtooth waveforms; sine or skewed “sine” waveforms; and narrow, square, or wide pulse waveforms respectively.

I replaced the original JFET-based tri to sine section with a differential BJT pair one.

A few problems on the first run PCBs but they’re fixable with some kludging. Some mistakes of mine, and a couple of problems with the Kassutronics circuit. I made corrections to the PCB but have not tested the corrected version.

I also updated design of the front panel, which should say “Kassutronics” rather than “Analog Output”.

Schematics, KiCad design files, Gerbers, and documentation in the GitHub repo: GitHub - holmesrichards/kdlfo: Shape variable dual LFO synth module in Kosmo format


I had a run of these made from the latest Gerber’s, and found that you need to re-fill your ground plane on one side of the board after the addition of the 200R resistors. I still managed to get it working with some bodging.

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Yikes, very sorry about that. The PCB and Gerber files should be OK now.

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No worries. A smart person would have checked them over before ordering. It did say they were not tested.