M50 aluminum membranes

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K Brown this is the earliest version of the M50 capsule. Neumann produced it from 1948 -52. This is a Neumann MM2 microphone built for anechoic chambers. Only 90 of them were ever built. Mine is no.50
I've never read anywhere that is the same capsule used in the M50 . . .

That would explain the thick diaphragm - a measurement mic.
 
Well I know that the nickel capsule was 0.8 micron but the aluminum diaphragm that came on my M50 capsule mounted on my MM2 measure a whopping 60microns thick which I cannot understand.
Even though we talk Neumann, i'm not sure they knew exactly what they were doing back then, and how hi-fi this thing is supposed to be, what hi-fi even meant in that period. For some of that old capsules i sometimes feel they were just happy if they worked.
 
If the customer is expecting this to ever sound like an M50, they're bound to be disappointed; this mic didn't sound like an M50 when new.
 
The MM2 I believe was the first measurement microphone or at least Neumann's. The internal structure of this capsule appears to be an M50 and it is omni. The thick diaphram may be because this was used for some industrial application. The MM2 is a large badge U47 amplifier (large transformer and capacitors) coupled to this omni capsule on a long extension. This was followed by the MM3 which used the AC701 tube and then the MM5 which used the KM83 capsule. ( after reading the info posted I see the MM5 had it's own proprietory capsule)

I own the mic so I'm expecting it to sound like an MM2 :)
 
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That's another clue. They write the membrane of the MM2 capsule is 10mm in diameter. M50 KK53 is 12mm...
Also, the capsule used in the M50 is diffuse field equalized. The MM2 is not as far as I know.
In the case of the aluminum one, actually 12.5mm.
 
The MM2 I believe was the first measurement microphone or at least Neumann's. The internal structure of this capsule is exactly an M50 and it is omni. The thick diaphram may be because this was used for some industrial application. The MM2 is a large badge U47 amplifier (large transformer and capacitors) coupled to this omni capsule on a long extension. This was followed by the MM3 which used the AC701 tube and then the MM5 which used the KM83 capsule.

I own the mic so I'm expecting it to sound like an MM2 :)
Oh, I though you were repairing it for someone. In any case, it's not an M50 capsule. According to the Neumann paper, the MM5 had an even smaller capsule than the 10mm MM2, so not a KM 53 (12.5mm).
 
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The MM2 I believe was the first measurement microphone or at least Neumann's. The internal structure of this capsule is exactly an M50 and it is omni. The thick diaphram may be because this was used for some industrial application. The MM2 is a large badge U47 amplifier (large transformer and capacitors) coupled to this omni capsule on a long extension. This was followed by the MM3 which used the AC701 tube and then the MM5 which used the KM83 capsule.

I own the mic so I'm expecting it to sound like an MM2 :)
Can you share some internal pictures of the capsule?
 
K Brown this is the earliest version of the M50 capsule. Neumann produced it from 1948 -52. This is a Neumann MM2 microphone built for anechoic chambers. Only 90 of them were ever built. Mine is no.50
I had been pm-ing some references (like the spreadsheet I see came up in the thread) but I will relate this here…

According to Uwe Sattler the MM2 capsule (1949) is not the same as the K53 Aluminum (1954), though it is what directly led to it. I’ll see what else I can find out for you about documented differences and the info you are looking for.
 
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Don't know if it was used in M50/KM 53, but the material was called Duralumin.
https://en.wikipedia.org/wiki/Duralumin
I’ve suspected it being Duralumin for quite some time. I’ve been interested in finding out the true thickness used for a long time. I’ve read 0.8-microns turned super-duper tight and with a 83pf measurement. Everyone has said that’s impossible; must be 8-microns. It seems no one knows for sure. Someone must know though!
 
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