When mounting different modules in one of my cabinets I ended up with a small empty space, 3HP. The reason for this is that I mixed “standard” 8HP modules (DIY and Doepfer) with 5HP and 10HP modules (Eowave). Since the space is too small to add much controls on a front panel, I thought about adding a small blank panel covering the empty space. But, on the other hand, you’ll always need to be able to split and sum signals, why I built a small 4-channel mixer and multiple. The module mixes up to 4 signals without any level controls, and distributes the mix to 4 independent buffered outputs.
The module works fine for both audio and CV signals, and can easily be soldered on stripboard.