The Lustraphone C51 Microphone

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A look at an old dynamic mic which doesn't work.
Opened case, stuff hanging out.

I found the reason for failure was the transformer secondary was o/c, so maybe it's a good idea to check if the capsule works well enough to be worth fixing the transformer.
The front of the capsule.
For testing the capsule I attached a random transformer, The ground wire is attached from the socket to the case and also the switch. In this mic the capsule is grounded and the transformer secondary floats as usual. I could have just connected without a transformer, but this was handy.
This transformer is about 1:7, but it will do just to get an idea of what it might sound like.
Empty rear case.

Typical manufacturing for this period. The diecast housing is good enough, built like a tank, but there are some details I don't like. Such as the crude design of the pivots, the cheap as possible switch and three-pin socket made from SRBP.
The original transformer.

I unwound the transformer to find the ratio. It is 80:1. The secondary is very fine wire about 2.5 mils diameter, maybe 42 guage? And broken in a few places unsurprisingly. It does say "High Impedance" on the front badge, but this is taking things too far I think.
Case front. Quite a nice piece of work, the slot is for the switch.
Rear of capsule. This is also high-quality, very solid and well made.
The rewound transformer in place.

I rewound with a 2:3 ratio. Sort of guesswork, but it will look fairly low impedance to most modern preamps. I have left the switch out of circuit so it does nothing.
Mic assembled before fitting front cover.
Rear view of mic showing the connector plug inserted. Or what remains of it. I think it would have had some sort of backshell once.