No info about availability.
4 in/1 out Audio and CV Mixer
MIX4 is a space conscious, 4 in/1 out, high quality audio and CV mixer. Originally set at unity gain (along with the VCA2), but tinkering provided useful intell and design changes. Upshot: With the pot set at 3:00 you are at unity gain, fully clockwise, expect a 2 Volt increase.
Four Pots
LVL 1, LVL 2, LVL3, LVL 4.
Five Patch Points
OUT, IN 1, IN 2, IN 3, IN 4.
All Controls and Patch Points
LVL 1 – Adjusts the level of IN 1.
LVL 2 – Adjusts the level of IN 2.
LVL 3 – Adjusts the level of IN 3.
LVL 4 – Adjusts the level of IN 4.
OUT – Composite output.
IN 1 – Audio/CV input 1.
IN 2 – Audio/CV input 2.
IN 3 – Audio/CV input 3.
IN 4 – Audio/CV input 4.
Vitals
Size - 6hp
Depth - 25mm with ribbon cable attached
Power Usage - 15mA
http://www.studioelectronics.com/products/synths/boomstar-modular/utility-modules/#mix4
These merchants probably sell this module. Huh?