PVC KK50 capsule for M 50; how rare?
Author: matthew mcglynn
Date: 11/05/2009
This is primarily a question for Martin Schneider, although I welcome input from everyone.

Martin's AES paper, "Omnis and Spheres - Revisited," states that the Neumann M 50 microphone originally was equipped with a KK50 capsule, and further that the KK50 had a PVC membrane.

Do any photos of this capsule exist? Do any production numbers exist -- meaning, how many KK50 M50's were sold?

Was the KK50 used in any other microphones, or was it developed for the M 50?

I'm trying to get a sense of how rare this original KK50/M50 was. I've talked to a couple people who have worked on vintage Neumanns, but they've never spotted a PVC-capsule M50 in the wild.

Is it possible that the PVC-capsule spherical omni was only ever used in the CMV3 bottle attachment, but not in the M 50?

Vielen Dank!  
Re: PVC KK50 capsule for M 50; how rare?
Author: Martin Schneider/Neumann
Date: 11/05/2009

the PVC KK50 was NWDR broadcast's idea of a capsule, used in '51-'54, together with MSC2 tube. Neumann then designed the metal diaphragm version, the KK53, for KM53 and M50. PVC just isn't suitable for high mechanical tension.

The KK50 capsule looks like KK53, only with gold-sputtered PVC diaphragm.

Most very early M50s were later reconfigured, with new capsule and/or AC701 tube and/or RF-protected connector version (a.k.a. "M250").
So, a surviving M50s with PVC KK50 will be quite rare, but quite probably it will need a new capsule, to work properly.

Best regards,
Martin Schneider / Neumann Mic. Development