Available as an assembled Module and as a DIY project.
This Module is currently available.
3 channel CV / Audio mixer with offset function
Three channel CV mixer with attenuverter on each channel. Channel 3 is normalled to +5 volts so with nothing plugged into this channel it acts as an offset, applying the offset to the mix of the other 2 channels.
With nothing plugged in to any channel the module can be used as a voltage source controlled by the level 3 knob.
Designed for CV but will work with audio