Standards for stacked depth-wise PCBs?

[NathanS]

Hello,

I'm currently in the process of building a computer orchestrated "highly parallel" synthesizer. This has been going on module-by-module over the past few years, where I draw up a module in Kicad and have JLCPCB manufacture them for me. Since JLCPCB (and, I assume, other less advertised companies) offers super cheap PCB fabrication and SMT assembly, the dream of having whole banks of VCOs, LFOs, and whatever else seems quite close.

The stumbling block I've found is that the current standards for rack-mount synthesizers don't seem to address much of what I'm trying to do. I've found no consensus on things such as mounting hole placement and board size --- particularly when dealing with stacked "Mezzanine style" configurations. There is the Eurocard(0) standard which defines the PCB mounting configuration fairly well; but I've never actually seen anyone mount a Eurocard PCB as described in the specification (like books on a shelf). I expect the best configuration for using many cards would be to have them stacked in line depth-wise, regardless. That way the depth of the relatively common 19-inch rack could be utilized.

Are there any standards for PCBs mounted as such? Ideally, such standards would be a super-set of the existing standards for front panels(1) and electrical interfaces(2) (Doepfer compatibility isn't a must, but they seem to have the most concise documents). I'd like to make a Kicad template based on agreed upon standards so that I don't have to keep experimenting with and redesigning my PCBs. Information on the best practices of modular-related PCB design would also be wonderful; but is perhaps out of the scope of the rest of this post.

If at all possible I'd like to avoid making my own standards. There are already too many poorly documented competing standards for modular synthesizers --- I'd hate to add another to the list. If it is truly something that hasn't been sufficiently standardized yet; then I'd make it a co-project to create those standards (hopefully with lots of input).

Thanks,

-- NPS

0. https://en.wikipedia.org/wiki/Eurocard_(printed_circuit_board)
1. http://www.doepfer.de/a100_man/a100m_e.htm
2. http://www.doepfer.de/a100_man/a100t_e.htm