This project was a bit tricky. At first I was not sure where to start. Do I want to use an opamp circuit or transistors for the logic part? Then I wanted to pack too many features in there. At some point I had a CMOS switch in there to switch audio signals as well but found out theres a ton you can do with a CV only design and my modular has enough VCAs and Envelope Generators to cover each and every possibility.

Features: 6 arcade Buttons that can be switched (on-on) to be always on (and break the connection) or always off (and make a connection). Each channel can be switched to their own output jacksocket or a mixed one (keyboard mode so to say) this switch can also mute the output (on-off-on). All channels are always mixed to produce a gate output (which is really only useful in always off in keyboard mode). The pots are voltage dividers that regulate the CV output of each channel.

Power: there is a barrel connector. The whole thing works with 5-12V but I currently use 9V.

Now there is a flaw to this regarding the use as a CV keyboard because it only holds the note as long as you press the button and it outputs a gate but if your envelope going into the VCA has a release then you’ll hear the root note the VCO is tuned to when the button is released. The solution is a gate to trigger converter and a sample and hold to sample the CV when the button is pressed. Then the sample and hold outputs the last sampled CV until you press another button. This works fine for my purposes.