So what is it?
It's a eurorack format voltage controllable electronic switching module.
The bottom section is similar to your old fashioned gate controlled bi-directional router. Functionally, it behaves very much like the Serge triple bi-directional router, though the circuit is very different.
The top section is based on a 70's delta modulator, (at least in concept). Delta modulation (DM or Δ-modulation) is an technique of analog-to-digital and digital-to-analog signal conversion. It's used for information transmission where quality is not of primary importance.
The signals being switched are also sent through a comparator & they control the switching. Plus you can add CV to all of this. Cool !
Muff's thread is here:
Andrew's build notes are here:
I have 2 versions of the PCB.
I'm currently building Version 2 (on the left).
Version 2 has corrections (mods) already done which you will read about in Andrew's build notes.
Mostly replacing some resistors (470K & 22K) & the addition of the 10K .
A 10 k resistor needs to be soldered from the left pad of the 470k resistor to +V, easiest is the closest pin of
the nearby transistor - the collector of BC547.
I've used 510 ohm SMD resistors for the LED resistors.
You need to experiment with this. I might go to a 1K for the next build.
Mount pots & Jacks. I used a 1M & a 100K pot ... using this for CV.
Cool. Looks like it works. I'll check this further tonight.
CGS - Bi-Directional switch.