Current plans:
- VCO #1
- http://www.fonitronik.de/application/files/7915/5922/3259/TH-VCO-MAXIMUS.pdf
- Positive polarity only
- VCO #2
- LFO
- https://www.davidhaillant.com/simple-lfo-1-5/
- No rate range switch (pick cap in between?)
- VCA
- https://benjiaomodular.com/post/2021-12-17-lm13700-vca/
- Replace one CV input with offset pot
- VCF
- https://www.schmitzbits.de/ms20.html
- Replace LEDs around A3 with triple diodes
- Envelope
- Wavefolder
- https://www.gerbster.nl/eurorack/wave-folder/
- Remove audio-in level
- Buffered Multiplier
- Delay
- Reverb
- https://sdiy.info/wiki/CGS_reverb
- Remove left output to output mono
- Sequential Switch
- Noise
- Sequencer
- https://benjiaomodular.com/post/2021-04-09-8-step-sequencer/
- Combine 3 random gates from noise and a CD4051 for random step selection
- Mixer
- Drum Machine
- https://www.gerbster.nl/tr82/
- Trigger push button and output jack on each drum source
- Internal 555 clock, external clock jack, clock out jack
- I2C LCD screen to display current status
- Rotary encoder to select drum and start/stop
- 16 step pattern switches (input read by 74HC147)
- LEDs on each step (output by 2x74HC595 - on/off XOR current step)
- Mixer with master output volume and stereo out jack