Available as an assembled Module and as a DIY project.
This Module is discontinued.
a cheap and simple VCO
the VCO 10 is a module designed to feel cheap, be cheap, but not sound cheap. It features sawtooth, triangle and pulse waveforms, as well as PWM and sync. Its wide range, from 2Hz to 40,000Hz, makes it a great modulation source, and as a sound source it does quite a decent job, having a usable range of up to 5 octaves. Of course it is not comparable to the ultra-expensive VCOs out there, but for the price there is absolutely nothing to complain about. The front panel is reversible so that if you don't like the stylized ocean wave pattern, you can have a more plain looking panel.
The module is available either fully assembled or in PCB/panel form, but not as a kit. More info on the website.