This is a diode ladder low-pass VCF and it will self oscillate, but only above 2KHz. It's designed to be 24dB/octave rolloff, but due to the circuit design it's less than this in practice.I think it has a relatively soft "bubbly" character.
I've added an internal white noise source, and gone for larger retro knobs.
This is a "one off" nostagia project, I'm not intending to market these.
Demo clip on Soundcloud (internal noise source then sequenced sawtooth wave - this is just the filter, nothing added):