Null-A: 42HP or stand-alone synth

This is a custom design for a local university to be used for teaching analogue synthesis, nearly done!

It has a pre-amp, Envelope follower, 8 stage sequencer with forwards/backwards control, clock divider - /2,/4,/8,/16, 2 EGs, 2 VCAs, 2 LFOs with a difference rectifier, VCO with PWM and a VC processed sawtooth out, Arp4023 VCF, 3 input mixer and a headphone amp. The cutout is for the 1/4" socket to feed the pre-amp & EF