Here is a view of the current VCO PCB. It uses the most recent VCO core design (circa 1976) and the shapers from the original Synthasystem. I've laid it out so you can use hand matched transistor pairs in the exponential converter, an SSM2210 or LS319 and a discrete PNP, or a THAT340 which has a pair of matched NPNs and PNPs (only one PNP is needed). The exponential pair needs to be in thermal contact with the PNP and thermistor and I thought the THAT chip would be a great choice. I've tested a THAT chip in the core and it worked fine.
I've included a 4 pin MTA connector ala MOTM and FRAC and some simple signal conditioning which was not present on the original. It can certainly be bypassed to have a "true" Steiner VCO. The input is marked +12 and -10 but I'm pretty sure it can be run on +/- 12 VDC. I've not tried it yet as I'm waiting for this "next" version PCB to arrive.
I have ground pads on each pot and jack rather than a star grounding system. I just haven't found this to be a problem and when I look at others who know much more than me, the layouts tend to be like this. I also tried to give enough room to use 0.1 inch center connectors for the pots, jacks, etc. I chose to not use PCB mounted pots so you can put it behind any panel you want.
I'm not posting the official artwork or schematic yet because I want test it all first and go over it with Nyle.
So enjoy, but this is not the final version, at least not yet and I can't guarantee it will work.
I'm happy to entertain suggestions on the layout.