I made a VCO that covers <0.03Hz through >13KHz out of crap and sticks!
6 generic op-amps, 3 generic transistors, 3 generic diodes, 1 capacitor and 20 resistors - and you, too, can have one TODAY, since my article on Ultra-Widerange Micro VCO is now out!
It's not a very precise VCO - it tracks exponentially and CV inputs can be tuned to track 1V/Oct over 2-3 octaves, but not more than that. But it requires no fancy or obsolete parts like a VCO chip or an OTA - just the most bread-n-butter parts ever. It's also a simple circuit and an easy build. If you were meaning to build an oscillator that is something more than an atari punk console, but all designs online are too complicated and have uncommon parts, this design just might be suitable for you!
Here's a basic sweep:
And here's some gross noise it and another VCO make in tandem!
As always, all the info, including schematics, circuit notes, more sound demos and module photos, veroboard layouts, etc, are in the article on my site. I'll drop the schem here, though, because for once i really like how it looks, despite in fact being a kinda hacky design.
(i actually think the only reason it doesn't heat up is because TL07x are too slow for that to happen lmfao)
