People, Schoeps didn't use a "proprietary" power connector.
Correct. The connector tip is DIN45323, which is not Schoeps proprietary.
I think that there are a couple of reasons people have been calling it proprietary 1) Redding Audio used to supply replacement connector assemblies, but when they ran out of them a few years ago (I bought their last one) they could no longer supply replacements. The part that Redding supplied was an assembly...consisting of the DIN45323 connector and an unterminated two foot long cable that was integrated with the connector. IIRC the Redding part was supplied with a Schoeps part number, but I'm not 100% about that.
It's literally a standard item (thus the DIN number)--and it was, and is (and presumably will remain) available from a number of sources in Europe if not elsewhere.
FWIW, I researched the availability of these three or four years ago and literally searched worldwide, which isn't necessarily to say that it's not available, but that I was unsuccessful after a concerted effort and making contact with the several European and US based sources that I was able to find on the internet. While the part can be found in the catalog listings of a number of sources, the actual availability of the connector for our purposes seems to be another story. The main issues were a) that the connector was not available on its own...it was stocked as part of a larger assembly that made the overall cost too expensive (something like $40 each in one case, if I remember correctly), and b) that they could only be purchased as a bulk purchase...the supplier would not sell say five or ten of them at a time.
I ended up finding a place in Europe that had ten pieces that I was able to make work for me...one end has the DIN45323 connector and the other end has the female side of an adaptaplug. I bought all of them and was able to make connectors for myself that work great. I think I made a couple of them for some other TSers. I do have the remaining connectors, but I've moved recently and they're in storage up in Pennsylvania so there's no way I can get my hands on them right now.
Here's a supplier with a US presence:
https://en.globtek.com/news/molded-din-45323-style-low-voltage-plug-provides-a-low-cost-alternative-to-assembled-type-in-power-supply-and-low-voltage-cabling-applications
Richard...I looked into this supplier and communicated directly with their sales department. I cannot recall what exactly was the issue, but the bottom line is that they would not sell me individual DIN45323 connectors. It seems like the guy told me that they only make this connector for one of their industrial customers who orders it as part of a larger assembly or perhaps they order it so that it can be mass produced by them as part of a larger assembly. Nevertheless, they wouldn't sell me a small quantity of them.
That's not to say that someone else would get the same story if they tried, or that this situation hasn't changed in the last 3 or 4 years since I tried.