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U 87 Ai vs ???
Old 26th November 2005
  #31
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nukmusic's Avatar
 

hummm wondering if the u87ai can be modified to match a U87 or U87i or U67? heh

link 1

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Old 26th November 2005
  #32
Gear Addict
 

This entire argument is rediculous. The U87ai is one of the best sounding mic's around. I've recorded & mixed several top ten hits in my career, ALL of which were cut with a U87ai.
Old 27th November 2005
  #33
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Quote:
Originally Posted by nukmusic
hummm wondering if the u87ai can be modified to match a U87 or U87i or U67? heh
Dangerous science fair experiment follows....

The U87Ai uses the K67/K870 capsule which is (not surprisingly) the one used in the U67. This can be done because to get a figure-8 pattern, you have available both positive and negative voltage on the DC-DC converter.

The original U87 did not have this option available, so the capsule was constructed slightly differently. The stamped aluminum spacer used between the capsule halves was changed to a stamped plastic spacer, and the four screws used to hold the capsule halves together were modifified to have plastic sleeves on them so the two backplates could be isolated. This would be somewhat difficult to modify - you'd need to rewire and get a replacement K87 capsule or maybe a while KK87 head.

Electronically, it would be possible to modify the mic, but I don't know if you necessarily want to do that because you would need to change out the capsule as well.

One other change between the old U87 and the new U87Ai is the frequency response of the amplifier was changed by changing some values in the equalizer section. These could actually be changed to the old U87 values, which would give you a slightly darker tone. One option for the experimenter would be to reduce the output of the DC-DC converter, which would reduce the polarization voltage to 46 volts (instead of 60) - easy to do by changing one zener diode. That is what was done on the U87 but remember that the U67 used 60 volts, and you'd basically give up a few dB of output and noise. There would be a very slight change in frequency response but it should be less than a dB, but then you wouldn't have to change the capsule.
Old 27th November 2005
  #34
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paterno's Avatar
 

From the Neumann site:

"The letter A in the name indicates a more recent generation, as compared to the U 87 i microphones that were built from 1967 to 1986. Modifications apply to the electronic components of the microphone only; the capsule remained unchanged.

The present-day circuitry increases the operational headroom of the U 87 Ai by supplying the bias voltages for the capsule through a reduced resistance. The result is a higher sensitivity of 10 dB for identical sound pressure levels, and an improved S/N ratio of 3 dB."


There are some recent threads about the 87ai, which you may want to search for. I know I posted my impressions of it when I used one about a month ago. Try this thread...

John
Old 28th November 2005
  #35
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Anderson's Avatar
 

U87 Ai vs.... Brauner phantom V or Valvet.

Try them out. Great Mics. A bit U47-ish actually.

Cheers
Old 29th November 2005
  #36
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Quote:
Originally Posted by paterno
the electronic components of the microphone only; the capsule remained unchanged.
Mechanically, this is true. Electrically, the backplates of the older U87's are isolated to facilitate connection in the figure-8 mode. The new U87Ai connect the backplates together and use a DC to DC converter to generate the opposing voltages required for figure-8 mode. Refer to the service information (schematics).
Quote:
Originally Posted by paterno
The present-day circuitry increases the operational headroom of the U 87 Ai by supplying the bias voltages for the capsule through a reduced resistance. The result is a higher sensitivity of 10 dB for identical sound pressure levels, and an improved S/N ratio of 3 dB."
Technically, this is correct, but only because a DC to DC converter has a negative resistance characteristic. The U87i is polarized with 47 volts (remarkable with 48 volt power), according to my U87i service information, where the U87Ai clearly has an additional circuit board (where the old photoflash batteries went) which is the DC to DC converter board used originally in the U89. The voltage output is marked as 60 volts, which should result in slightly more output. The other circuit change is in cardioid mode, the U87Ai disconnects its back membrane, whereas the U87i leaves it in-circuit which poses a load on the active (front) capsule when in cardioid mode. These changes, when combined, would give pretty much the results that Neumann is claiming on their website.
Old 29th November 2005
  #37
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SoZo's Avatar
Quote:
Originally Posted by dale116dot7
Mechanically, this is true. Electrically, the backplates of the older U87's are isolated to facilitate connection in the figure-8 mode. The new U87Ai connect the backplates together and use a DC to DC converter to generate the opposing voltages required for figure-8 mode. Refer to the service information (schematics).

Technically, this is correct, but only because a DC to DC converter has a negative resistance characteristic. The U87i is polarized with 47 volts (remarkable with 48 volt power), according to my U87i service information, where the U87Ai clearly has an additional circuit board (where the old photoflash batteries went) which is the DC to DC converter board used originally in the U89. The voltage output is marked as 60 volts, which should result in slightly more output. The other circuit change is in cardioid mode, the U87Ai disconnects its back membrane, whereas the U87i leaves it in-circuit which poses a load on the active (front) capsule when in cardioid mode. These changes, when combined, would give pretty much the results that Neumann is claiming on their website.


Man... you sure do know you microphones! Hmmm... which is better in your opinion the 87 or the ai?
Old 29th November 2005
  #38
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I work as an electronics designer, but in terms of mics, I'm a more of a serious hobbyist.

I'd probably pick one of the newer U87Ai's but I would for sure look at the mic's insides first. The older the mic, the more likely capsule work (cleaning, at least) would be required. U87's are also sensitive to moisture once the diaphragm has a bit of contamination on it. Jim Williams has apparently seen newer Ai's with SMD parts in them and I would try avoiding them... not so much for the SMD parts except that most capacitors in surface mount are ceramics and generally don't sound good. I've not heard a new 87Ai with ceramics so I can't comment.
Old 29th November 2005
  #39
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paterno's Avatar
 

Quote:
Originally Posted by dale116dot7
Quote:
Originally Posted by paterno
the electronic components of the microphone only; the capsule remained unchanged.

Mechanically, this is true. Electrically, the backplates of the older U87's are isolated to facilitate connection in the figure-8 mode. The new U87Ai connect the backplates together and use a DC to DC converter to generate the opposing voltages required for figure-8 mode. Refer to the service information (schematics).

Quote:
Originally Posted by paterno
The present-day circuitry increases the operational headroom of the U 87 Ai by supplying the bias voltages for the capsule through a reduced resistance. The result is a higher sensitivity of 10 dB for identical sound pressure levels, and an improved S/N ratio of 3 dB."

Technically, this is correct, but only because a DC to DC converter has a negative resistance characteristic. The U87i is polarized with 47 volts (remarkable with 48 volt power), according to my U87i service information, where the U87Ai clearly has an additional circuit board (where the old photoflash batteries went) which is the DC to DC converter board used originally in the U89. The voltage output is marked as 60 volts, which should result in slightly more output. The other circuit change is in cardioid mode, the U87Ai disconnects its back membrane, whereas the U87i leaves it in-circuit which poses a load on the active (front) capsule when in cardioid mode. These changes, when combined, would give pretty much the results that Neumann is claiming on their website.
thanks for the insight, Dale. I'm wondering what you mean by 'negative resistance characteristic'?
thanks,
John
Old 29th November 2005
  #40
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Having used both the ai's and older 87's I would say without hesitation that I greatly prefer the older ones (e.g., 70's), assuming they're in good shape. The new ones have a bright, sizzly top end I hate, but the older ones, when in good shape are full, warm and open, without being too bright. On some voices, in my experience, they're better than other mics that generally get lots of attention as good vocal mics (e.g., a good 67, most of the Soundelux mics, etc.) -- my 2 cents...
Old 29th November 2005
  #41
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paterno's Avatar
 

Quote:
Originally Posted by analogjeff
Having used both the ai's and older 87's I would say without hesitation that I greatly prefer the older ones (e.g., 70's), assuming they're in good shape. The new ones have a bright, sizzly top end I hate, but the older ones, when in good shape are full, warm and open, without being too bright.

-- my 2 cents...
Funny, I much prefer the ai's. Old 87's [and I've tried a lot of them over the years] sound dark,thick, and flat for my taste.

Microphones, go figure...

Cheers,
John
Old 30th November 2005
  #42
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Quote:
Originally Posted by paterno
thanks for the insight, Dale. I'm wondering what you mean by 'negative resistance characteristic'?
thanks,
John
A DC to DC converter is basically a constant power device. In a condensor microphone it doesn't matter so much because the load is barely anything. But for something delivering power to a real load, take this example:

1 watt load, 10 volts = 0.10 amps output.

If I power this off of a switching regulator (DC to DC converter), and power this with a 20 volt supply (assuming 100% efficiency for now), the current required for that one watt load is 0.05 amps at 20 volts. If I reduce the voltage to 15 volts, the current will rise to 0.067 amps. Note that the current rises as the voltage drops. That's the negative resistance.
Old 30th November 2005
  #43
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saskatchewan's Avatar
 

The 87 seems to be very unpopualr these days... all the more reason to grab a used one. Honestly , this is a great mic. Sure it's not a 47, 67, 251 or C12... but you can guarantee that the 87 has made a place for it'self in the history of classic mics. I've been borrowing a pair fo 87Ais for a while and I've used other 87s quite often and I'll say that they are often the first mics I reach for, mind you I don't; have any of the other above mentioned mics.... I do have 2 AKG 414EBs, 2 AT 4050s, 2 Km 184s 2 Rode NT1000s (yeah I know these don't count).... and frequently use a MG UM 70s (which I really like). The 87s are really in their own league...

C'Mon, give it up, this is the last good mic that Neumann still makes...
Old 30th November 2005
  #44
Kai
Gear Nut
 

Brauner VM1 !
Old 30th November 2005
  #45
Quote:
Originally Posted by dale116dot7
I work as an electronics designer, but in terms of mics, I'm a more of a serious hobbyist.

I'd probably pick one of the newer U87Ai's but I would for sure look at the mic's insides first. The older the mic, the more likely capsule work (cleaning, at least) would be required. U87's are also sensitive to moisture once the diaphragm has a bit of contamination on it. Jim Williams has apparently seen newer Ai's with SMD parts in them and I would try avoiding them... not so much for the SMD parts except that most capacitors in surface mount are ceramics and generally don't sound good. I've not heard a new 87Ai with ceramics so I can't comment.

I have one here with the new surface mount daughter board for the front end preamp. They used to use polystyrene caps off the capsule, now it's the dreaded monolythic surface mount ceramic caps which do sound like crap. These add harshness to the top end. They then went to a surface mount tatalum gain shunt cap. These design flaws are also found in all the TLM mics, KM100 series and even the KM105 vocal mic. Bypassing the tatalum cap with a polypropylene film cap helps. Replacing the input ceramic cap with a MIT MultiCap does seem to fix the hard top end and softly open up the 20k details.

Sennheiser has really messed up this company. Reminds me of what CBS did to Fender in '69. What I can't figure out is why all the stoned deaf hippies picked up on that in 3 months where all the golden audio ears haven't figured out the surface mount problems for many years.

Maybe if they all smoked some dope or dropped some acid they might then become aware of it?

Or maybe musicians, even in a stoned stupor, can pick up things the audio guys can't?

Jim Williams
Audio Upgrades
Old 21st December 2005
  #46
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oceantracks's Avatar
 

Quote:
Originally Posted by Yiannis
I know that it is a classic mic dude but I just said that I have never heard someone saying that it is a "fantastic sounding mic"

fantastic sounding mic mean's that its THE mic, but I don't think that a lot of people are happy with the results on vocals!!

am I wrong guys?

To make it more clear I am not AGAINST Neuman! tutt
I do like a lot M 149-km84-184-Tlm 103.

Yes, you are wrong. There is no "THE" mic, there is "THE" mic, for "THIS" singer, on "THIS" tune....

That said, I'd be willing to bet more records have been made with an 87 on vocals than any other mic. Must be a reason.

I also think, whether you like their music or not, Karen Carpenter sounds pretty awesome. Almost all her stuff was sung through an 87. Yeah, I know, she could sing through a Radio Shack, blah, blah, but ....they used 87s.

I think also that the 87 takes EQ very well. It doesn't always sound impressive out of the box, but during a mix, it doesn't fight you. I think many people nowadays want to plug in a mic and say "Testing..." and hear perfection. Some of the newer mics are so hyped that they sound great out of the box. Then in the mix, it's a different story.

I'd take an 87ai over anything in it's price range today. It also leaves you the option of sending it to Klaus Heyne for his mod, which is pretty wonderful.

TH (JMHO of course)
Old 21st December 2005
  #47
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ISedlacek's Avatar
Quote:
Originally Posted by oceantracks
I'd take an 87ai over anything in it's price range today. It also leaves you the option of sending it to Klaus Heyne for his mod, which is pretty wonderful.

TH (JMHO of course)
Having U87 ai , I would like to ask what the "Klaus Heyne mode" does to the microphone. Is it a permanent change ? How does it project to the microphone sound ? And also how much does it cost ? Do you have it done ?
Old 21st December 2005
  #48
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oceantracks's Avatar
 

Quote:
Originally Posted by ISedlacek
Having U87 ai , I would like to ask what the "Klaus Heyne mode" does to the microphone. Is it a permanent change ? How does it project to the microphone sound ? And also how much does it cost ? Do you have it done ?

You can check with Klaus on his forum up here about prices and specifics.

The studio I used for years had one of theirs modified by him and it killed everything. It opened the mic up quite a bit, in general just gave it lots of clarity that it didn't have out of the box. It is a permanent change, in that he removes circuitry from the mic that is superfluous and was only in there because the BBC mandated it or something years ago. Again, ask Klaus. I believe the mod is around 2K. But you end up with a world class mic, and they cost that much anyway.

TH
Old 21st December 2005
  #49
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ISedlacek's Avatar
Quote:
Originally Posted by oceantracks
I believe the mod is around 2K. But you end up with a world class mic, and they cost that much anyway.

TH


Oh my ... It already cost that much or even more before the mod ...
Old 22nd December 2005
  #50
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Quote:
Originally Posted by ISedlacek


Oh my ... It already cost that much or even more before the mod ...

Some of the most popular mics are over 4K...this mod puts that 87 in that league in the opinion of some people, myself included. I think it's nice to know it can be done. You can buy the 87, live with it a year or so, and upgrade anytime (I'd wait for the warranty to run out from Neumann first!). So it's just nice to know you can do it, with many mics, there is no way to mod them. Klaus feels the diaphragm of the 87 is a classic, and the superfluous electronics are all that holds the mic back from realizing it's full potential.

TH
Old 22nd December 2005
  #51
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ISedlacek's Avatar
Quote:
Originally Posted by oceantracks
Some of the most popular mics are over 4K...this mod puts that 87 in that league in the opinion of some people, myself included. I think it's nice to know it can be done. You can buy the 87, live with it a year or so, and upgrade anytime (I'd wait for the warranty to run out from Neumann first!). So it's just nice to know you can do it, with many mics, there is no way to mod them. Klaus feels the diaphragm of the 87 is a classic, and the superfluous electronics are all that holds the mic back from realizing it's full potential.

TH
Yes, it is now No1 in my next year gearlust list ...
Old 3 weeks ago
  #52
I have 87Ai and my "second best" microphone is AKG C414 XLII.

Regarding the main question "what if not 87" it's hard to tell while not having dozens of very expensive mics in a drawer... What can I say then ?

My 87Ai also does not like Focusrite: neither 430MkII nor 428. It sounds jus "ok" but it is not what I expected considering the price of this equipment ! It sounds very good with NEVE 8801 though.

In some scenarios I like 414 XL II better than 87. Actually I think that you can't go wrong with 414XLII (not XLS). I don't know these ancient "brass" 414's and honestly I don't care. Before I had 87 I worked most vocals / acoustic guitars with 414 XLII and I was more than happy. Please mind that 414XLS is very different microphone and I don't like it.

If there is a tight budget then RODE is a good option and SeElectronics never seemed to be a good choice for me.

Best, Tom

PS My 414XLII is made id 2006 so it is one of the "new" ones with electronic switches.

Last edited by vasylek; 3 weeks ago at 10:32 AM.. Reason: spelling
Old 2 weeks ago
  #53
Gear Head
 

all I know is I posted a blind shootout here with a U87ai, gefell um 70, gefell um92, akg c414, wunder cm7s and shure sm7, and the u87 won by far. of course, no one thought they were picking the u87.
Old 2 weeks ago
  #54
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toledo3's Avatar
 

completely unsurprising! ha. :-)
Old 2 days ago
  #55
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JblKid95's Avatar
 

I’m still surprised a u87ai is under 4,000$. Used prices are a steal if you know what you’re doing. Very versatile mic. They don’t all sound the same unfortunately. The newer ones made from 3 years ago and up might be the ones though. I’ve heard about 3 of the new ones and they all sounded the same. Just like the one I have now but much airier with a slight bump at ten K or a harmonic of ten k. I once had three in my possession. one had a very very steep roll off with resonance in the mids, some night call “honk” but it still sounded good, full and vibey. one was very flat and clean in the mids and airier. The other one was so fuzzy I sold it immediately after I learned and saw that it had some sort of chip and not the transformer like the other two (CIRCUIT DIAGRAM X). Alot of u87s in circulation actually have that chip, but the newest ones don’t. 90s 87s Dont have that chip either. They say circuit diagram. I think the one I ended up picking is diagram 6. Sent klaus random sound files of the two without the chip and he picked the flat one with the airy highs everytime. He picked the same mic, even with different titles

Last edited by JblKid95; 2 days ago at 06:28 PM..
Old 2 days ago
  #56
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Klaus's Avatar
 

I have mentioned the circuit changes in U87Ai previously. Here is a chart that you should just copy and save, so you know which circuit is in your mic (silver sticker with circuit # on the back of every transformer):

Circuit Diagrams:
02: Standard-U87A Neumann (FET: 2SK3819 or similar, selected)
03: DC/DC-converter board: omit U89 components (from ~1995)
04: PCB 4 in place of discontinued FET (from 2002 to 08/2013)
05: 2 values of components on DC/DC-converter board changed (2011)
06: return to single FET in place of daughter board PCB 4; DC board
same as 03, plus changes from 05. (since 08/2013)

As you can see, ONLY #s 04 and #05 have the dreaded "daughter" board installed, instead of the single FET. I also posted this as a new tread, for easier look-up
Old 2 days ago
  #57
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Yes that’s it. Someone else also posted it. It’s been some years. Just going off memory. Around that time I had many u87s including a nice vintage one that funded my current 87ai lol... what a waste of time, but atleast I found the right one.
Old 2 days ago
  #58
Gear Addict
Hi, there!!

Can someone tell me how old is this 87Ai, that I bought recently? Looks like new, btw. Please, look at the attached photos.

Thank you!!
Attached Thumbnails
U 87 Ai  vs ???-img_20200503_175555.jpg   U 87 Ai  vs ???-img_20200503_175718.jpg   U 87 Ai  vs ???-img_20200503_175346.jpg   U 87 Ai  vs ???-img_20200503_174437.jpg   U 87 Ai  vs ???-img_20200503_175320.jpg  

Old 2 days ago
  #59
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Klaus's Avatar
 

As I have posted many times in the past: Neumann does not cross-reference serial numbers and manufacturing dates, but serial numbers and delivery dates (to the respective distributor). Even in-house, that fact is no longer made clear by the personell that answers inquiries.

If you want to zoom in on the manufacturing date of any U87/A, you need to find the date codes of components, like capsule, electrolytic capacitors, etc. Or study circuit revisions, plastic color/materials used, layout of components, printing styles, etc. etc.

Without that information, my estimate: your mic was built in the late 1990s.
Old 1 day ago
  #60
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90s 87s are nice. Redman recorded a lot with one, basically a lot of the dope 90s records. One forum member Wunderbros probably owns the best 90s 87 I’ve ever heard. My records are posted on here somewhere. I never dip the highs or high mids. I actually push them a lot/add distortion and have one of those annoying high mid voices. Something I definitely couldn’t do with 99% of mics I’ve used from Elam to c800g. The lows of these mics in great condition are connected to the highs. Something that I haven’t heard outside neumann
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