R/E/P Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1] 2  All   Go Down

Author Topic: U87i & U87ai....Differences?  (Read 16145 times)

Working Musician

  • Newbie
  • *
  • Offline Offline
  • Posts: 7
U87i & U87ai....Differences?
« on: May 21, 2004, 03:15:13 pm »

I was able to purchase a u87i in great condition which after checking the seriel number, found out was made in 1974. Was curious to know what the major differences were between the "i" and the "ai" which took its place in 1987.

The battery for internal power and its meter in the "i" series was the only real physical difference I noticed. I heard through other sources that the "ai" had a raised output level.

Any information appreciated.


Mark Baker
Logged
Regards
MJB

Klaus Heyne

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3154
Re: U87i & U87ai....Differences?
« Reply #1 on: May 22, 2004, 03:56:33 pm »

I am sure David Satz could execute a precise, all encompassing narrative of the differences.
In the meantime I try a Klutz version:

The central difference between the U87 and its successor U87A was the introduction of a DC-DC converter in the new model (the 'i'-suffix identifies an XLR connector, which all U87A and most U87 have anyway.)

What is a DC-converter?  It is a circuitry ,situated in the space where the battery compartment of the old U87 was, that increases the phantom power's available 48VDC to 60 VDC, and thereby polarizes the capsule voltage with 12 more volts than in the U87.
The extra volts available at the capsule increase the output of the mic by about 10dB. The side effect of the output improvement is a slight reduction in headroom (distortion from very loud sound sources) by 5-6 dB.

All other audio and EQ parameters of the two mics remain the same.

One other advantage of the DC converter is that now the U67 capsules and the (identically constructed) U87A capsules, known as K870, are interchangeable.  

The old U87 capsule required an isolation washer between the capsule halves, to generate three patterns out of 48V, which made the U67 and U87 capsules not interchangeable.

Kind regards,
Logged
Klaus Heyne
German Masterworks
www.GermanMasterworks.com

Henrik Vogel

  • Newbie
  • *
  • Offline Offline
  • Posts: 36
Re: U87i & U87ai....Differences?
« Reply #2 on: May 23, 2004, 08:29:51 am »

Klaus Heyne wrote on Sat, 22 May 2004 21:56


All other audio and EQ parameters of the two mics remain the same.



They do? I have never been in the position to compare a U87 and a U87ai side by side, but what I hear from others is that the ai is brighter which many people seem to dislike. Are you saying this isn't so?

Best,
Henrik Vogel
Logged
RECORDISTA! pro audio

David Bock

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 333
Re: U87i & U87ai....Differences?
« Reply #3 on: May 23, 2004, 02:47:17 pm »

It's true the amount of HF rolloff is reduced in the more recent U87.
regards,
DB

Klaus Heyne

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3154
Re: U87i & U87ai....Differences?
« Reply #4 on: May 24, 2004, 03:30:15 pm »

The Neumann frequency plots of U87 and U87A show a difference of high frequency peak in the 7-10k region of less than 1dB between the two models (facilitated by a change of the HF Eq cap from 220pf to 160pf.)

I am not sure whether less than one dB difference qualifies as "the same" or "brighter".  "Harder" may be a better term, caused by the significantly "stiffer" polarization voltage.

Logged
Klaus Heyne
German Masterworks
www.GermanMasterworks.com

Loco

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 508
Re: U87i & U87ai....Differences?
« Reply #5 on: May 24, 2004, 05:11:36 pm »

Henrik Vogel wrote on Sun, 23 May 2004 08:29

I have never been in the position to compare a U87 and a U87ai side by side, but what I hear from others is that the ai is brighter which many people seem to dislike. Are you saying this isn't so?


As the Ai is louder, people may say it is "clearer" or bright. It could be confusing. However, as it is easy to overload internally, it is easy to overload preamps as well with it.

And they seem to load differently the preamp or something. You cannot make one sound like the other simply by changing the gain on your Pre. Your vocals will get a different edge between both models, none of them my favorite flavor of U87. My choice is the U87Ki.
Logged
Carlos "El Loco" Bedoya

"There's no right, there's no wrong. There's only popular opinion"   Jeffrey Goines
http://www.tukanart.com

David Satz

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 661
Re: U87i & U87ai....Differences?
« Reply #6 on: May 24, 2004, 06:29:37 pm »

Hello, loco--

Pray tell, what is a U 87Ki?  Is that a U 87i with potassium added?

(or by chance might it be a "highly Klausified" U 87i ?)

--best regards
Logged

Loco

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 508
Re: U87i & U87ai....Differences?
« Reply #7 on: May 25, 2004, 11:33:34 am »

Is potassium what Klaus adds to the U87?

Klausified, indeed. The desert-island Mic. I have yet to find a vocalist that won't suits this beauty.
Logged
Carlos "El Loco" Bedoya

"There's no right, there's no wrong. There's only popular opinion"   Jeffrey Goines
http://www.tukanart.com

Klaus Heyne

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3154
Re: U87i & U87ai....Differences?
« Reply #8 on: December 10, 2010, 06:52:49 pm »

Update:
This thread was started in 2004, and since then, in addition to surface finish changes, two additional things have been incorporated in the U87A:

1. The discrete FET has been replaced with a sub-circuit board containing several surface mounted solid state components: Neumann could not find a decently quiet and reliable single J-FET anymore on the market, and substituted it with a new circuit.

2. The K870/67 capsule performance has changed. There are several threads where this is discussed (someone with a bit more time than me may want to help and link these threads.)
To summarise: The low end is tighter now, most likely due to higher tension of the two diaphragms, and most likely to reign in manufacturing tolerances/reduce rejects/save money.
Logged
Klaus Heyne
German Masterworks
www.GermanMasterworks.com

kats

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1694
Re: U87i & U87ai....Differences?
« Reply #9 on: December 11, 2010, 12:06:15 am »

Klaus, when were these new changes ushered in?
Thank you.
Logged
Tony K.
http://empirerecording.ca

Entertainment is a bore, communication is where it's at! - Brian Jones 1967

Klaus Heyne

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3154
Re: U87i & U87ai....Differences?
« Reply #10 on: December 11, 2010, 02:25:00 am »

Around serial number 85000 the new sub-board was introduced in the U87Ai. This would have been ca. 2005/6.

Around the same time, or maybe a year later, the K870 capsules started to sound noticeably drier in the bass (not ALL capsules, but many.)
Logged
Klaus Heyne
German Masterworks
www.GermanMasterworks.com

Donn Halliburton

  • Newbie
  • *
  • Offline Offline
  • Posts: 36
Re: U87i & U87ai....Differences?
« Reply #11 on: December 12, 2010, 01:35:54 am »

Would it be possible to see a picture of the difference between circuit boards, like an A/B pre/post sub circuit board?

Donn
Logged

radiovinheta

  • Full Member
  • ***
  • Offline Offline
  • Posts: 156
Re: U87i & U87ai....Differences?
« Reply #12 on: December 13, 2010, 08:47:29 am »

"Several surface mounted solid state components" on "newest" u87Ai?... OH MY GOD!!!!!  Mad  Mad  Mad
That's why i DON'T LIKE any new NeumannHeiser mic.

Logged

MagnetoSound

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2589
Re: U87i & U87ai....Differences?
« Reply #13 on: December 13, 2010, 09:32:46 am »

Klaus Heyne wrote on Fri, 10 December 2010 23:52

Neumann could not find a decently quiet and reliable single J-FET anymore on the market




Really? What happened?


Logged

Music can make me get right up out of my chair and start dancing or it can get me so pumped up I have to walk around the block.
It can also knock me back and make me sit there and cry like a little baby. This shit is as powerful as any drug!!!
- Larry DeVivo

Klaus Heyne

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3154
Re: U87i & U87ai....Differences?
« Reply #14 on: December 13, 2010, 01:41:30 pm »

If you remember, demand for high-quality discrete FETs, especially of the Texas Instrument-pioneered 2N3819 variety, dried up in the 1990s. Who needed them anymore? Everything went to SMT technology, so discrete solid state components were no longer in demand, and high-quality samples of these discretes were no longer manufactured. With other words, except for some off-shore junk, that model FET was dead.

This has now changed. Fairchild has just reintroduced their version of the 2N3819. I am about to test them (Andreas Grosser sent me some), and have high hopes. This does not mean that Neumann will re-tool. We will have to see. The extra step of biasing each FET individually (as it was done with discrete FETs) may be too much of a cost factor for Sennheiser to green-light it.
Logged
Klaus Heyne
German Masterworks
www.GermanMasterworks.com
Pages: [1] 2  All   Go Up