I was thinking of an expanded update for the matrix mixer. 3x3 attenuverted pots + a set of overall gain control for each channel + gain amount switches
So you wouldn’t need an inverted section, because each channel can be inverted or not.
I hope the middle point or zero is easy to set though. the overall gain might help with that a little.
What was it that was said about chaining inputs?
more on topic: the CMIX is ordered.
8HP panel
3 normal ins with pots
3 inverted ins with pots
2 outs
Some mods are possible for keying effects (like the Matrix mixer), but I have added no
dedicated MODpoints as the pcb is tightly packed. so (there is) no space left!
(on the pcb I mean, not space in general) 
thanks, that is what I meant. edited the sentence for ultra clarity!
Bom and Schematic are here for download:
| CMIX BOM v1 2020 | |||
|---|---|---|---|
| Resistors | value | details | amount |
| r1, r2, r3, r4, r27, r30 | 100k | 6 | |
| r5, r6, r7, r8, r14, r24, r26, r29 | 499r | 8 | |
| r9, r10, r11, r12, r13, r15 | 1k | 6 | |
| r17, r18, r19, r20, r21, r22, r23, r28, r31 | 10k | 9 | |
| Ferrite beads | |||
| f1, f2 | 2 | ||
| Diodes | |||
| d1, d2 | 1n4001 | reverse power protection | 2 |
| Capacitors | |||
| c1, c2 | 10uF | >16v electrolythic | 2 |
| c3, c4, c5, c6, c7, c8, c9, c10 | 100nF | Ceramic, 2.5mm | 8 |
| IC | |||
| u1, u2, u3, u4 | 8pin socket | optional | 4 |
| u1, u2, u3, u4 | LM6172 | 4 | |
| Power | |||
| SV1 | 10pin | shrouded header | 1 |
| power cable | 10pin to 16pin | keyed headers | 1 |
| Hardware | |||
| Pots | b10k | vertical 9mm Alpha | 6 |
| Jacks | Thonkiconn | 8 | |
| Knobs | 6 | ||
| M3 screws | for panel mounting | 4 |
Build tips
Use this order for placing the components:
Just got my pcb set yesterday, many thanks @reverselandfill!
Here is a quick test, shapes are generated using CMIX (H ramp, V ramp, 3x Cadet VCO, 1x Castle VCO), then sent to VU002 for doubling, the 4 outputs goes to Matrix Mixer, then to RGB encoder, and further processed in composite using CBV002.
Resistor placements to help you build the CMIX while I continue to write the build manual 
see also here
