I've a pair of kk83 capsules that I was told came from Neumann recording consoles (they were used as talkback mic elements!)
Anyway, the capsules look very nice but I am questioning where to make my connections as there is a perfboard material behind the backplate with a yellow lead on it. Also there is a pin sticking out next to the lead in the center. And, there is a "stud" which appears to have had a lead soldered to it at one time - protuding from the side of the capsule.
The capsule is mounted via a rubber gasket to an L shaped bracket. I have a nice circuit to use these with but I don't want to damage anything.