A CV Sync + MIDI and eventually soft-synth Sequencer that I wrote myself for the BBC micro in early/mid 80s.
The CV side used to drive a TR606, TB303 and a DIY modular while I added the midi for a CZ101 that I bought around 85/86 I think.
The 'soft-synth' was a mono additive using the ADC chip in the BBC micro and an external analog filter chip (cant remember which). Laster added sine wave tables in external memory chips and hardware summing to an external ADC - very grainy, but was an interesting and (never realised at the time) quite forward project for the time
Audio was recorded to a very old (valve based) ampex reel to reel.