Thank you Klaus for that info.
I had a chance to check out the microphone today. Considering the nuvistor, it sounds quite nice. The back side of the capsule seems to sound a little nicer than the front side. There's also a bit of noise, and the home-made power supply is amateurish and has to go... I'm sure it's not doing the sound of the mic any favors.
I took some detailed photos. I'd love any insight into what we have here.
Serial No. 3082
BV8 transformer-- "BV No. GN 8"
K47-- would this have been made in 1963 or 1973? An older replacement perhaps, or perhaps replaced when the Nuvistor retrofit took place?
K47 rear side... a bit dirty, but looks nice enough to me.
This 1µf capacitor is branded Bosch and has the designation "MP." I'm not sure about the meaning of the star of David ink-stamped on it, but it's certainly peculiar. I'd rather not speculate on the origins of that mark. Is that a date code of 1956?
I'm not sure if this green capacitor would've been original or not, but it doesn't look familiar to me-- I suspect it's some sort of replacement. Its make is "ERD" in a shield logo, and it says "MKT 1813" along with "0,47 µf" "±10%" and "400V RD"
Tiny 1/4W carbon composition resistors up top, in the 100M and 60M values. A little surprising to me that they'd have used carbon comp resistors in that location-- they don't look like other 47s I've seen. Unoriginal? The orange .01 capacitor... is that an axial ceramic? Odd choice for that location-- is it normal?
One side
...and the other. A clearly-unoriginal mix of low-cost carbon film and metal film resistors here. I'd suspect these should be changed out for something nicer. No clue why they were replaced in the first place. The 100k carbon film hanging off the end looks odd, but I'm not looking inside 47s every day.
One end of the cable has this connector that looks like it may have once been a part of a stand mount, but it's missing a piece. Not sure if it's even possible to locate the part to complete it.
Would love any info, input, or thoughts.