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Author Topic: U87 Vintage: Many Questions  (Read 1190 times)

Astuck

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U87 Vintage: Many Questions
« on: December 19, 2016, 10:53:47 am »

Hello Klaus, hello guys,
I'm Arno, I'm a recording engineer.
I recently acquired a vintage U87 7pin tuchel.

I've opened it, the transistor gate pin solder was broken, plastic chassis broke too, solder jobs have been done poorly by previous "tech guy". I had to rework the beast and clean the pads. I've several questions as my dismount process goes on :

1) Do you have an idea of the era of this one ? (Neumann was contacted yesterday)

2) There is no branding/ref on the transistor at all, was it common at this time or was it done on purpose or did the time erase it ?

3) The capsule was supposed to be K87 but the red markings around let me confused


4) As you see the capsule is really dirty, solder jobs were poorly done, in case this K87 is genuine, can you send me (PM) your prices for capsule cleaning and restoration ?

5) The R19/R20 pads are inactive, output transformer is wired in serie (200ohms) but mesuring it reads 59ohms between pin2&3, is this a normal behavior ?

Thanks a lot in advance for any infos you could give !

Arno Stuck
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Astuck

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Re: U87 vintage several questions
« Reply #1 on: December 19, 2016, 10:55:26 am »

Bad solder :
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Astuck

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Re: U87 vintage several questions
« Reply #2 on: December 19, 2016, 10:56:37 am »

Output transformer wiring for 200 ohms :
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Astuck

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Re: U87 vintage several questions
« Reply #3 on: December 19, 2016, 10:57:15 am »

Capsule :
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Astuck

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Re: U87 vintage several questions
« Reply #4 on: December 19, 2016, 10:57:54 am »

Front :
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Astuck

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Re: U87 vintage several questions
« Reply #5 on: December 19, 2016, 10:58:22 am »

Back :
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Astuck

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Re: U87 vintage several questions
« Reply #6 on: December 19, 2016, 10:59:11 am »

Capsule 2 :
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klaus

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Re: U87 vintage several questions
« Reply #7 on: December 19, 2016, 12:47:13 pm »

Hello Arno,

1) Do you have an idea of the era of this one ? (Neumann was contacted yesterday)

Other mics with similar serial numbers were delivered (not made, as Neumann does not publish or keep manufacturing date records) around January 1975. Usually the manufacturing date in that era for that mic was at the most a few months earlier.

Quote
2) There is no branding/ref on the transistor at all, was it common at this time or was it done on purpose or did the time erase it ?
Yes, it was common that Neumann would obliterate the parts number of the FETs which were either a 2N3819 or, more likely, an S 2436.

Quote
3) The capsule was supposed to be K87 but the red markings around let me confused :
"JTM 05.2004 MSP" or "STM 05.2004 MSP"
Can you give me a help with this ?
The capsule was rediaphragmed by Siegfried Thiersch in Möschlitz, East Germany, and as such will not produce the famous Neumann K87 sound. I would recommend to replace it with an original Neumann capsule. The high price for a vintage or even current U87 is derived to great extent from the mic's capsule, and without it you cannot achieve a U87 sound.

Quote
4) As you see the capsule is really dirty, solder jobs were poorly done, in case this K87 is genuine, can you send me (PM) your prices for capsule cleaning and restoration ?
I would not recommend to spend more money on this capsule. I would leave that decision to the next owner.

Quote
5) The R19/R20 pads are inactive, output transformer is wired in series (200ohms) but measuring it reads 59ohms between pin2&3, is this a normal behavior ?

When the output transformer is strapped for 200Ω IMPEDANCE its DC-RESISTANCE is around 60Ω.
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

Astuck

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Re: U87 vintage several questions
« Reply #8 on: December 19, 2016, 01:29:13 pm »

Hello,
Thanks for all of these explanations, you're a great help and your forum is a gold mine !

Arno
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rsmor

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Re: U87 vintage several questions
« Reply #9 on: January 19, 2017, 10:50:24 am »

Hello,
Thanks for all of these explanations, you're a great help and your forum is a gold mine !

Arno


Hello, I am brand new to your forum and I wasn't sure how to properly post. Hope this is an acceptable way.

I have a U87 which I love like my firstborn!  Sounds absolutely great.  Only slight problem, the switch for changing pickup patterns has become very difficult to move.  Could I just carefully spray it with a little studio lubricant, do you think?  Anyway, the main reason I came here was to see if anyone could tell me what year it was made:  Serial 25945.  Have owned it since the early 1980's. 

Any info would be greatly appreciated!

Thank You.

Roger

Ps:  I have since posted this question more directly to "Klaus".  I think I did, anyway.  New to this.
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klaus

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Re: U87 vintage several questions
« Reply #10 on: January 19, 2017, 12:36:13 pm »

Fall or winter of 1975 would be your mic's manufacturing, or more precisely, its original delivery date.

Do not spray anything into the head assembly which contains the switch assembly. It's a super high impedance area, and any liquid can compromise the impedance.

Besides, the cause of the pattern selector's impediment to movement is most likely not lack of lubrication, which is lifetime, but a bent section in the purple/black painted metal plate which shows the patterns: its tail ends sometimes get caught on the plastic protrusions of the head assembly against which it moves, and bends.

Though likely not yielding professional results* you can re-bend the metal plate where it is visibly distorted with smooth-cheeked needle nose pliers, after taking the head assembly off the mic amp. Observe that the arc of the plate and its ends are not over-bent, so they don't get caught anymore, and you should be done.

*which require removal of the head basket, removal of the pattern switch, removal and reshaping of the metal plate, then reassembly of these components.
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

rsmor

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Re: U87 Vintage: Many Questions
« Reply #11 on: January 19, 2017, 01:29:39 pm »

To Klaus:

Wow, was that ever fast!   Thanks you very much for this information.

Great site you have here!

Roger Moreau
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