Kai, I like the idea of using several small ProtoBoards for those circuit segments that benefit from segregated ground planes. I also agree that, for examining general circuit behavior, these boards might be of some use. I'm not sure how you deal with the excessive wire lengths under such circumstances, but since you've decided this is a good way for you to proceed, you have surely worked that out.

I bought a couple of these boards, large ones, one that's complete with built-in power supply and regulator (5-volts) back in the '70's, when nobody thought much about clocks faster than 100 MHz. However, aside from voltage regulators and small, simple, low-frequency transitor amp's or op-amp circuits and equally low-frequency relay circuits, I've seldom found them to be of any use at all, even when I routed multi-kHz signals through a coax.

When I've seen the work done by others, on similar boards, I frequently found common paths for voltage return and ground reference, which I'm sure you'll agree is a mistake, and long wire loops that pick up the local radio stations. This was not so much a problem for digital circuits when we used standard TTL, LSTTL, and ECL, but now that everyone uses CMOS, with its ultra-high impedance inputs, it's more troublesome because of the capacitive coupling between adjacent lines on the ProtoBoard.

I'm sure these have their place, perhaps on the kitchen table, but not in my lab.

RE