RCA 74B by John Eppstein
This vintage ribbon mic (standard figure 8 pattern) was introduced in the 1930s as the budget mic in the RCA line and continued in production up through the 1950s. It was a standard at small radio stations and studios, and is often seen in newsreels of the day. Its rated frequency response (only 50Hz-9kHz) belies its smooth, detailed sound. It is a multi-impedance mic, selected by changing an internal connection (don't do this yourself), with 50, 250, and 1500 ohm impedance available. The output is quite low and requires a quiet, high gain preamp. The mounting is a ball and socket swivel on the bottom of the mic with a 1/2 inch pipe thread - it requires an adapter for modern stands. (It does not use a yoke like the more expensive RCA models.) The motor is a long ribbon design (about 4.5 inches) with massive alnico magnets. Don't get this mic near your tapes or, heaven forbid, the heads on your recorder. Or the magnetic strip on your credit cards, for that matter.) The ribbon is EXTREMELY delicate - do not blow into this mic, drop it, or subject it to high SPL sources. (The ribbon in mine is currently in need of replacement.) Output is on a pigtail cable. The original had cloth insulation (over rubber IIRC) and will probably need replacement if it hasn't been already.
So if it's such a pain, what's it good for? Why bother?
Well, because of the tone. It's got it. It sounds like an RCA - great on vocal when you want that classic vibe, great room mic. Can be the sound you're looking for on acoustic stringed instruments if you need to tame the twang. It's very "round" without losing detail. And they go for a lot less than the RCA 44s and 77s (although current selling price is still around 14X the original 1930s price)
I rated this mic "n/a" in "bang for the buck" because if you're looking for bang for the buck you're probably not in the market for a vintage RCA, anyway. That being said, I found mine at a flea market for $100, needing a ribbon and new cable, which I consider great bang for the buck. May you be so lucky!
In case you haven't figured it out yet, I love this mic, taken for what it is, not what it isn't.
Edit: AARRGGH! It won't accept "n/a" for a rating. So consider my rating in that category to be n/a, because there's really no way to rate that.