This CV Mixer system is an adaptation of Ray Wilson’s design found in his Multi-Function module from the essential MFOS website.  I wanted to make a modular design with minimal wiring.  All pots are soldered to the PCB whilst the sockets connect to a 5 pin single row IDC.  This way you can use ‘each side’ of a 10 pin IDC to connect 2 mixers at a time to your socket panel.  I made a socket panel which has 2 x 10 pin IDC connectors so 4 mixers can be connected.  Built into my socket panel is a Common Input which buffers this signal each of the 4 CV 1 inputs.  Inserting a plug into a CV1 input socket breaks the buffered signal.

This system I built for my 4x HMVCO1a so I have wired each mixer output to its corresponding oscillator via the ‘normalled’ pin each CV input socket.

Each CV Mixer gives you :

A coarse voltage bias

A fine voltage bias

3x CV inputs with attenuators

A bi-polar LED indicator showing polarity of voltage