YuSynth Steiner VCF

Another one of the wonderful VCF designs from YuSynth. The VCF ‘core’ is the same as the design from YuSynth, I just replaced the rotary switch with a ‘digital’ version controlled by a Atmel ATTINY22 and a ADG412 digital SPST switch. This allows you to select 2 more modes, namely HP+BP and LP+BP, next to HP, BP, LP and AP (LP+BP+HP).