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M149 tube
Author: Posted by Han
Date: 03/31/2004
Hi all
A couple of years back my M149 started to be quite noisy. It turned out to be the 6111 tube and after it got replaced by a new one, the mic sounded like new.
I had to pay the bill which was about some $400.
Today an engineer told me the 6111 tube is listed for $6.75 I'm aware of the fact that Neumann uses the best tube out of many, but is that a fair price?
 
M149 tube
Author: Posted by M. Schneider / Neumann
Date: 03/31/2004

Dear Han,
while I'm not the one calculating end prices, there's some things I can say.
- True, you can get a 6111 for a few US$. These are all from those manufacturers we found completely unsuitable for microphone applications, after having test bunches of 100 pcs each. - In the end, there is only one type we use in the M149, and the price we have to pay for it is markedly higher, especially as the suppliers know that stocks aren't unlimited. - The tube has to be pre-selected, even with this manufacturer. - I presume you have a very early M149, which were still fitted with 8254 tubes. In this case, definitely the whole tube module has to be replaced when switching to over to the 6111.
I hope these explanations help...
Best regards, Martin Schneider Neumann Mic. Development  
Re: M149 tube
Author: Posted by Han
Date: 03/31/2004

Thanks, the mic is an exellent mic, no doubt about it and indeed it's an early M149. I've bought it new in sept. 1996
The tube got very noisy after some two and a halve years and indeed the small card where the tube is soldered on got replaced.
I still have the old module and the type of the tube is probably on a place I can't see. I can see AMPEREX and HOLLAND, which is funny 'cause it seems the tubes are made some 60 miles from where I live.
I still think the replacement was very and much too expensive.  
Re: M149 tube
Author: Posted by Marik
Date: 04/01/2004

Dear Mr. Schneider,
First, I would like to tell that I highly regard many Neumann's microphones and at different points owned some 'classics'--SM2, U47tube,U67, U87, KM54. I was the person Han refered as 'engeneer' in his post. For different studios I have serviced and repaired literally hundreds of microphones, including Neumanns. If you don't mind I have a few questions:
1)As Han has mentioned, his tube became noisy after some 2 and half year. We all know that normally (esp. preselected) the tube should be fine for at least 20-30 years. Considering that you use 'special selected tubes', which priced quite high, do you have any warranty, which covers that, or every two-three years your customers have to pay some $400 for replacing the tube?
2)As I understand, first M149's were with 8254 tubes. If you could tell me please, I am interested to know the reason why later it was replaced with 6111? Is it a quality reason, or 8254' availability?
3)A few years ago friend of mine replaced his AC701 (which is by far much more expensive tube than 6111) in his forty years old M50. If I remember correctly, he payed $350. I am interested to know what makes 6111, (even specially selected) $50-$100 superior than AC701, considering that it goes noisy in two and half years?
Thanks, Marik  
Re: M149 tube
Author: Posted by Marik
Date: 04/01/2004

BTW, I just wanted to let you know. About three years ago I inquired your service center about rediaphragming my shot KK67 capsule. I did not get any reply. Three months later I emaled again and never got a reply either. The capsule is still in the closet...
Best regards, Marik  
'Rediaphragming' a capsule
Author: Posted by David Satz
Date: 04/01/2004

Marik,
I certainly don't speak for Neumann, but it's my fairly clear impression that they don't 'rediaphragm' any capsules--they treat the entire capsule as a single, replaceable part. This makes sense technically since it is important for the two halves of the capsule to match one another closely (for the 'omni' and especially the figure-8 patterns), so it it preferable to make the halves of the capsule separately and test them, then choose two which have the same sensitivity.
If you 'reskin' one or both sides of an existing capsule you will get whatever degree of symmetry you happen to get--and I would imagine that the only way to bring it within specification would then be to try again, and perhaps again, and again ...
The designation KK 67 which you mentioned actually refers to the entire 'head' of the U 67 microphone, which includes many other expensive parts in addition to the capsule; thus it costs considerably more than the capsule alone. If you need to replace only the capsule, the needed part would be the K 67.
However, since this same capsule is now used in the U 87A microphone, but the designation 'K 87' was already used for the capsule of the original U 87, your capsule is usually called 'K 870' or even 'K 67/870' nowadays.
--best regards  
Re: 'Rediaphragming' a capsule
Author: Posted by Klaus Heyne
Date: 04/02/2004

Just a short note of appreciation, David. You are a master of concise explanations, and the Neumann Pinboard is all the reacher for having you.
Kind regards, Klaus Heyne  
Re: 'Rediaphragming' a capsule
Author: Posted by Klaus Heyne
Date: 04/02/2004

...and, of course, all the RICHER too!  
The Pinboard itself 'knows' a lot by now
Author: Posted by David Satz
Date: 04/02/2004

Hello, Klaus--
Many thanks for the kind words. I would agree that I'm a great guy, but as far as I am aware all the information in my post is available from other postings that have been made on this Pinboard in the past plus a little common sense.
Unfortunately this Pinboard doesn't have an FAQ page, and its search feature for past messages is not especially effective--messages aren't classified by subject area, so the great majority of search 'hits' on a given word or phrase are often irrelevant. And I would guess that relatively few people bother to use the search feature simply because it may not occur to them to do so. They may be newcomers with no way to know that the great majority of general questions have already been answered many times--or they may simply wish to ask their question and have it answered for them in the most straightforward way, which is understandable.
It has been hinted that a reorganization of the Pinboard is being planned. If so, perhaps there could be some division of the messages into 'topic areas.' That would help people to find information that has previously been posted and to ignore what does not interest them--as long as messages are clearly and honestly titled, and are placed into the categories to which they really belong. Unfortunately if people posting the messages don't do those things spontaneously and willingly, the classification would depend on the moderator, and the cost to his time would then become a big disadvantage of this approach.
But for example, there could be separate 'areas' to discuss microphone selection and usage; accessories; maintenance and repair; theory and practice of microphone design; the history of the company and of microphones in general; and the history of particular microphones--i.e. serial number lookups. And maybe there should be a section for those perennial inquiries that begin with 'Why doesn't Neumann ...' -- though those questions and their answers tend to be so repetitive in nature that they probably deserve a special section of the FAQ.
--best regards  
Re: The Pinboard itself 'knows' a lot by now
Author: Posted by M. Spahrmann / Neumann
Date: 04/05/2004

Dear Mr. Satz,
Thank you for your suggestions. Yes, Neumann is working on a new forum. The anticipated release date is the AES in Berlin.
The new forum will contain an improved search engine that allows to search the subject and/or the content and something more. In addition we plan to offer several forums for different topics.
The forum will also contain some additional improvements...
Kind regards, Georg Neumann GmbH Matthias Spahrmann - Advertising Department -
 
Re: 'Rediaphragming' a capsule
Author: Posted by Marik
Date: 04/07/2004

Thank you David,
I wish Neumann's custormer service let me know about it three years ago.