Topic: Anyone familiar with the Neumann KM-88?

[Teen Wolf Blitzer]

Have been pondering selling the 140's and picking up a pair.  I know I lose the lowpro setup but would gain m/s, split omnis and blum.     Anyone ever used this for recording or have an recordings?  Keep in mind these would be used more on stage or close to the sound stage.  Rarely am I in a section type environment.
Thanks for any comments! Edit to add:  And I assume these are side address so they would run vertically?






These appear to be newer? Are they still made?  But I do see them all the time and most look to be in great shape.

http://cgi.ebay.com/Pair-NEUMANN-KM-88-Vintage-Condenser-Microphones-KM88_W0QQitemZ260351833226QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item260351833226&_trksid=p3286.c0.m14&_trkparms=72%3A1240%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50

[Shawn]

I was very tempted by a pair in the past but after doing a lot of research I was scared off.

Apparently the mics are fairly fragile and neumann can not repair them any longer. The capsules are unique and haven't been produced in 20 years. The diaphragms  are made from nickel and can not be replaced. Also the component that controls the rear capsule is prone to failure and can not be replaced. I found a post on the neumann forums form an employee that said they would be weary of purchasing these mics without having them checked out by neumann first.

[Teen Wolf Blitzer]

That's enough to scare me off!     Thanks for the info.  So I assume that Ebay pair is still old but not as old as the other.  They look new to me.

[mikesalvo]

thats a sweet looking mic. Never heard of/seen this model. Thanks for the post. Not that Im in the market for mics,but if I were and I was considering these, the above mentioned "deal breaker" points would def. persuade me against it. Just outta curiosity what does a pair of these run used?

[audBall]

/note to self:  next time I sell mics, take pics of them on the accenting colored driveway

[Teen Wolf Blitzer]

lol.  I never noticed that.  It is on concrete isn't it?  Sketchy.

[H₂O]

I was very tempted by a pair in the past but after doing a lot of research I was scared off.

Apparently the mics are fairly fragile and neumann can not repair them any longer. The capsules are unique and haven't been produced in 20 years. The diaphragms  are made from nickel and can not be replaced. Also the component that controls the rear capsule is prone to failure and can not be replaced. I found a post on the neumann forums form an employee that said they would be weary of purchasing these mics without having them checked out by neumann first.

Are you sure that you are refering to the km88 and not the km56?   The KM 88 seems to be in the same family as the km 84/85 series (http://www.neumann.com/?lang=en&id=hist_microphones&cid=km88_publications) which use similar capsules to the 184/140.   I thought Neumann stopped using Nickel capsules in the early 60's and these seem to date from the late 60's - late 70's.

The KM 56's is a 3 pattern AC701 Tube based mic that definitely uses nickel capsules and are extremely delicate.

UPDATE - Found additional info saying that the caps are nickel with the KM88's - nevermind.

[DSatz]

H2O, the KM 88 was in effect the solid-state version of the KM 56, and used the same fragile (and now essentially unavailable) capsule. Nice sounding for sure--I used to own a pair of them--but not very practical for most users.

An additional difficulty in assembling a pair of this model nowadays is that during the final few years of its production, Neumann revised the capsule design in a way that markedly decreased the capsule's low-frequency response when set to the cardioid or (especially) figure-8 patterns.

The photo above appears to show a microphone of the later type, with the revised grille having a wider aperture between the slats. But this actually doesn't correlate entirely with the change in the capsule's frequency response, so you can't just tell which is which by looking. (The capsules were sold separately as replacement parts, and so were the grilles.)

--best regards

[illconditioned]

H2O, the KM 88 was in effect the solid-state version of the KM 56, and used the same fragile (and now essentially unavailable) capsule. Nice sounding for sure--I used to own a pair of them--but not very practical for most users.

An additional difficulty in assembling a pair of this model nowadays is that during the final few years of its production, Neumann revised the capsule design in a way that markedly decreased the capsule's low-frequency response when set to the cardioid or (especially) figure-8 patterns.

The photo above appears to show a microphone of the later type, with the revised grille having a wider aperture between the slats. But this actually doesn't correlate entirely with the change in the capsule's frequency response, so you can't just tell which is which by looking. (The capsules were sold separately as replacement parts, and so were the grilles.)

--best regards

Wow.  A lot of insider (?) information here.

I'm intrigued by the metal diaphragms again.  Nickel?  Isn't that was high grade measurement mics (like B&K omnis) made of?
At the moment I'm looking for a (cheaper) set of measurement type mics (1/2" capsule, free field, prepolarized).  Any pointers to sources of these?  I tried G.R.A.S. (Denmark) and they quoted me ca. $1000 each(!).  Theirs is 1u Stainless steel maybe even better than DPA/B&K.

  Richard

[DSatz]

Richard, yes, during the early and mid-1950s all the major manufacturers used nickel (or in some cases, aluminum) diaphragms for their small-diaphragm microphones. Tensilized polyester (Mylar) film in the appropriate thicknesses (anywhere from 3 to 6 microns) became available in industrial quantities around 1958 (I would have to check--that's from memory). Within a year or two nearly all the manufacturers had dropped nickel like hotcakes, in favor of the much more durable, reliable, and manageable plastic material. At the same time Neumann abandoned their use of PVC substrates for their large-diaphragm capsules, and switched those designs over to Mylar as well.

[dactylus]

Please correct me if I'm wrong but doesn't Microtech Gefell still use nickel membranes in their M70 & M94 capsules as well as their complete line of "Measuring Microphone Capsules"?  I own pairs of M70 & M94 caps and I am very pleased with their sound.

http://www.microtechgefell.de/eng/home.htm

Also for anyone considering mics with nickel membrane caps I would suggest contacting Peter Drefahl of drefahlaudio.com.  Peter possesses a wealth of definitive information on vintage European microphones.  Peter could give you his take on the Neumann KM-88 and possible capsule options.


I purchased a second pair of Gefell M70 (nickel) capsules late last year and I'm going to have Peter reskin them for me (one cap was damaged).  Peter has developed a hybrid metal alloy membrane that he says is sonically identical to the nickel membranes, but that is much more durable than the nickel membranes. 

I'm going to have Peter reskin my 2nd set of M70 capsules this year with the "hybrid metal alloy membranes" and then compare them to the nickel membrane M70's. 

Peter Drefahl is top notch in his craftsmanship, expertise and knowledgeability of European microphone rehab and history.  Plus Peter is one heck of a nice person!!


http://www.drefahlaudio.com/mic/1_ref.html

Peter Drefahl  - http://www.drefahlaudio.com/

Check out Peter's photo gallery, pic of a restored Neumann KM-88 on this page along with other heavyweights...

[DSatz]

> doesn't Microtech Gefell still use nickel membranes ...

M 94, yes (see below), but I think the M 70 was originally PVC-based and that more recent ones are Mylar-based, though I'm not entirely sure.

As I said, "nearly all" the manufacturers abandoned the use of metal membranes rather quickly when Mylar became available. For two big reasons, Neumann (Gefell) was an exception. One is that in the 1950s they were behind what we used to call "the Iron Curtain," and couldn't legally deal directly with Western suppliers such as DuPont; they also lacked hard currency to do so. For many years Gefell's materials and parts quality lagged far behind those of Western manufacturers, and it is very much to the company's credit that they did as well as they did with what they had available to them.

The other is that Gefell has always been a producer of measurement microphones as well as studio microphones, and I was speaking mainly about studio microphones. Neumann (Berlin) also used to produce a line of measurement microphones with small, nickel diaphragms, but they discontinued their measurement mikes at around the same time as the switch to Mylar.

Of course standard measurement microphones are pressure (omnidirectional) transducers, which as a rule aren't used as often for music recording as directional microphones are. Gefell's nickel cardioid capsule, um, shares many design elements, shall we say, with Neumann (Berlin)'s capsule for the KM 54 microphone--see attached photo--and ironically (or perhaps I should say nickellically?) Microtech Gefell is one of the few places that can bring a capsule from that series of microphone up to spec now that Neumann (Berlin) (or Wennebostel now that they're a branch of Sennheiser) no longer has the process to do so.

For pressure-gradient capsules there is essentially no question that Mylar is a superior material to metal in every respect. For pressure transducers, which operate at much higher diaphragm tensions, some people feel that metal still has its advantages from the manufacturing aspect.

Sonically, in capsules that can accommodate either type of diaphragm, the difference is small. I actually had a pair of microphones not long ago in which unbeknownst to me, one capsule had a nickel membrane while the other one was Mylar, and I didn't notice any difference either before or after I found out about it. So I don't think that this is any big part of our Holy Grail pursuit. Makes sense, since the majority of the moving mass of a capsule is the air surrounding the diaphragm, not the diaphragm itself--and the motion of that air is controlled by friction within the capsule (i.e. capsules don't work like tympani, or they'd have "one-note" frequency response like tympani have).

--best regards

[dactylus]

^

Thanks as usual for the wealth of information DSatz!!

From the Gefell product info:  It appears that the Gefell M70 capsule contains "a nickel diaphragm in front of a PTFE-plated electrode".  PTFE = Teflon

Gefell MV692 and Associated Capsules PDF 

http://taperssection.com/reference/pdf/gefell-692-um70-m69-m70-m93-m94.pdf


The MV692/M70 microphone is equipped with a capsule with cardioid characteristics and functions as a combined pressure/pressure gradient transducer.  The converter element contains a nickel diaphragm in front of a PTFE-plated (polytetrafluoroethylene) electrode.  The coating of the electrode serves to increase performance reliability.


PTFE:  Polytetrafluoroethylene

http://en.wikipedia.org/wiki/Polytetrafluoroethylene

[PH]

Microtech Gefell is one of the few places that can bring a capsule from that series of microphone up to spec now that Neumann (Berlin) (or Wennebostel now that they're a branch of Sennheiser) no longer has the process to do so.

I'm surprised to see DSatz mention bringing KM54's up to "spec" considering this post......

there are no "factory specs" for reskinning a Neumann capsule, since Neumann simply does not specify their capsules in this way. They don't repair their own capsules, let alone advise or support other people in doing so. All such claims are therefore quite bogus.

[DSatz]

Good catch, nashphil. You've manage to hoist me on my own figure of speech.

If I recall correctly, though, in the message you quote I was talking then about an eBay ad in which someone had made a whole thing about how the capsule of a microphone they were selling had been "reskinned to Neumann specifications." I was suggesting that people not put too much faith in that claim, since Neumann has no specifications for doing any such thing. They don't even do it themselves, let alone encourage third parties to do it. And since that ad was placed by a well-known international dealer in used Neumann microphones, it's for darn sure that they knew this.

I discovered a few years back that the phantom powering circuit in a very well-known tube mike preamp was wildly out of spec. I called the manufacturer and was told that the circuit followed "the AES specification" for phantom powering. Now, the AES doesn't have a specification for phantom powering; it's an IEC specification. It's one thing if the manufacturer didn't happen to know that, but it's another thing to make stuff up in the hope of fooling a customer, no?

Anyway, Microtech Gefell is willing, to a limited extent, to restore Neumann (Berlin) capsules the best they can as a favor to their own customers (i.e. Microtech customers who also own old Neumann (Berlin) microphones that can't be repaired any more by Neumann), and the KM 54 is a prime example. I'm not in any position to verify their claims--or anyone else's--as to the adequacy of such restoration. I have doubts all around, frankly.

Unfortunately, not only does Neumann not have any more of that type of capsule available, nor can they remanufacture the membranes, but they're also out of Telefunken AC 701k vacuum tubes and the original output transformers. So buying a used KM 50-series microphone these days is a very risky proposition. Even some microphones of the KM 60 series are unsalvageable nowadays if you insist that authentic parts be used.

--best regards