Friday, 16 August 2019

PE Minisonic VCF

I've finally got around to assembling a Eurorack  version of the Voltage Controlled Filter (VCF) from the Practical Electroncs magazine "Minisonic 2" Synth. The Minisonic was the start of my synth DIY journey, around 1979. While bits of my original Minisonic circuity are probably still around hiding in other equipment, the VCF "disappeared", so it's good to hear it again after about 35 years!
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):