Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Noah Scot Snyder]

Well, the plot thickens. I received the M934A and it fits just fine. I believe that may mean these microphones are the same as the microphone pictured in both links I posted previously. No photoshopping, I assure you. I still keep thinking that these mics are some version of the m221. The only thing I think I can say for sure is that they seem to be rare microphones indeed and they sound amazing.

[Noah Scot Snyder]

...

[panman]

I believe that may mean these microphones are the same as the microphone pictured in both links I posted previously. No photoshopping, I assure you. I still keep thinking that these mics are some version of the m221.

It really seems to be as you say, but they are all M155:s, because mine is definitely M155 and the insides look the same. I never had a chance to see a M221A. Neither is there any info or schematics to be found. It begs for the conclusion, that M221A and M155 are the same mic in fact. Would be nice to know for sure, though it would make some of my previous statements invalid. Is there really nobody, that owns a M221A? As to the M934A, that you now have, looking the pic you posted, I clearly see the thread diameter beeing bigger than in mine. Yours is marked M934A, but as I now checked mine, it only has "Nr 457" written on it. My conclusion is, that the first badge limited amount M221(no A or B) is the rare odd-ball with smaller thread and M155 and M221A share the same housing-tube and thread size. This link shows Telefunken M221, that is the same as mine: http://www.filmsoundsweden.se/backspegel/schoeps.html. There again the capsule only has the sn. marked. I would post pics, but my camera-battery just went flat. Of course they are all versions of M221, but as the schematics show, they do differ some bit.
Inspired by this thread, I mounted the M155 innards into a M221B body with M934B. The M221B housing has a larger inner diameter, so the electronics stay a bit loose, but with the set-screws it was possible to get it tight enough to do some AB:ing against the M221 having that 934-type capsule. There is a noticeable difference in volume M221 beeing louder, but M155 has better bass-response also extending lower. Otherwise they did not really differ much sonically. Did not check the trafo wiring yet. Could be the 50 versus 200 ohm difference. M221 has the phase flipped for some reason that I cannot figure out. Perhaps the European versus American standards differing those days. From before I do remember M221B beeing slightly louder than M221 again.

[David Satz]

I have only limited information about this, but there definitely was a model M 221 A, as well as an original M 221 which was neither "A" nor "B", and finally a model "C" was manufactured as a small, final batch many years later. There are differences in the mechanical fittings of the capsules (threads inside the body sleeve vs. threads outside, differing in pitch as well) and in the "A" type, the polarization voltage was generally 60 Volts while in the "B" type it was generally 120.

However, there is at least one schematic published for the M 221 by Telefunken which seems to be a hybrid of "A" and "B" types. Perhaps as many as three variants of the "B" circuit were produced at different times. And the M 155 in general is very sparsely documented; I have never been able to find out why this model even existed as separate from the M 221 series. But so far as I know it was made exclusively for Telefunken, never for Siemens or Philips, and wasn't sold under the Schoeps label, either--so the answer probably lies in Telefunken's commercial concerns rather than anything on Schoeps' side of the arrangement.

Schoeps has only very limited internal documentation concerning many of their older products, the people who designed and built them are no longer available to be asked about them, and a fair amount of information has had to be reconstructed in retrospect. To complicate matters, Telefunken's documentation and product literature often doesn't track with Schoeps' as far as the use of the "A" and "B" is concerned, creating some curious anomalies and "time paradoxes".

This is about as much as I know on the subject. I get the impression that in these matters, one has to deal with whatever is in front of one's eyes and nose, and not try too hard to make it fit properly into any one, definite schema.

--best regards

[klaus]

...in the "A" type, the polarization voltage was generally 60 Volts while in the "B" type it was generally 120.

Are you sure? It's been a while since I worked on them, but I don't recall such high voltage on the capsule. Maybe you meant B+, rather than capsule polarization voltage?

[usattler]

According to the schematics posted in this thread and elsewhere, at least the Telefunken M155 and the Schoeps M221B have their capsule biased by 120 V, the Schoeps M221 and M221A feature a 2:1 voltage divider and bias their capsule with 60 V. That fact may also be responsible for the level difference observed in a previous post.

[Noah Scot Snyder]

Thank you all for sharing your fine thoughts. With your help I am continuing to learn about these microphones. I may yet be able to rely on them for recording.

[Noah Scot Snyder]

Just wanted to happily report after replacing a faulty power supply (evidently a capacitor problem) these mics are finally quiet enough for me to us recording orchestra. I deeply appreciate all your help and I'm both lucky and pleased that the mics themselves are in such good condition.

[klaus]

Thanks for your Abschlussreport!
KH

[Timjag]

Out of interest does Martin at Madooma have any info on them? I recently bought a NOS W28 windshield for C28A from him and he was extremely helpful. He clearly has his resources for finding all this (lovely) old junk, I would have thought he would have some history on them.

[klaus]

Why not ask him directly?

[Noah Scot Snyder]

I did ask Martin, and Andreas Grosser as well as Berhard Vollmer and many other sources that were all generous with their knowledge, but no one had any info on the CM9b capsules or this version of the 221. They do sound great and I like the M934A capsule as well. It sounds different from my M221B with 934B capsule but has its own beautiful tone.