Neumann U47 and Similar Mics

Discussion in 'Recording Studio' started by Nicky, Oct 30, 2016.

  1. Nicky

    Nicky On The Road Less Traveled Premium Member

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  2. Blues Bird

    Blues Bird Member

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  3. LPSGME

    LPSGME Senior Member

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    I wish they would had included a vintage 47 of decent quality.
     
  4. Progear

    Progear Premium Member

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    I was missing the low mid harmonics of an original u47... best bang for you $, you can't beat the slate mic system... JMHO....
     
  5. LPSGME

    LPSGME Senior Member

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    I would have been nice had they run them through a vintage tube pre besides the Neve 1073.
     
  6. JJ Blair

    JJ Blair Senior Member

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    Nothing does what a U47 equipped with a K47 capsule, VF14 tube and BV8 transformer does. I own three of the real thing, and I've tried them all. (I'm leaving out M7 capsules, because no original M7s exist within factory tolerances, due to PVC striking and hardening.)

    When Oliver Archut was alive, he was able to build variants of the BV8 that balanced the low end to work with other tubes, but it still never did that same "midrange authority" that a VF14 equipped mic gives you.

    The Slate is snake oil. In a mix, it will sound close, but it doesn't do what the 47 does, and definitely not when you start using it in some of the distant applications where a 47 sounds so nice, aside from close miking technique.

    And it won't give you the 47 omni experience, which is responsible for some of my favorite vocals. The sheen that adds to top end is superb.

    The Neumann M147 is a POS. Avoid the M149. Overpriced IC electronic crap, with a tube stuck in for marketing purposes. The Telefunken VK14k tube is meh. It's a glass tube stuck in a can. I heard an EF14 equipped Wunder that worked OK, but lacked a little thump. The Bock 507, which not a 47 copy, is amazing. Worth trying, but not cheap. Flea is making good stuff. Worth trying out. Everything else isn't even close.
     
  7. yeti

    yeti Senior Member

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    Tell us how you really feel, JJ:cool:
    I'll go out on a limb here and say that while I totally accept your judgement in these matters I'd also like to say that IMVHO none of it makes one bit of difference. The "U-47 sound" is a mirage to an awful lot of people waxing about it due to so many variables after close to 70 years in existence and various states of (dis) repair.. If the U47 would have never seen the light of day it it's original form and all these tracks would have been cut with a different Neuman variant they would have sounded just as great to us, the listener. And the slate mic just seems like utter nonsense to me, a mic is so much more than some digital emulation you slap on some average condenser mic. it's behavior, pickup pattern, reach, etc. can't be modeled. try modeling a Schoeps CM 41s off axis response using some cheap-ass pencil condenser, it isn't going to happen, ever.

    The slate is to mics what a Kemper Profiler is to tube amps, close enough for those who can't hear the difference anyway but not close enough to those who do have the skill to discern. I'd use it anyway because if it sounds good it sounds good.
    The idea to recreate a classic mic that's no longer re-creatable is baloney and beneficial at the same time. It's baloney because there are so many exceptional mics for every application out there that "not having a U47" is never an excuse but it's also beneficial because it's geeks that try to nail it who push the envelope just like 40 years of trying to build a guitar that's just as good as a 50's Gibson has resulted in the general public having access to guitars at prices and quality levels unthinkable a few years ago. same with mics, you can cut great vocal tracks with $300.00 microphones, if you can't , don't blame the mic.
    It's been said that you have to experience a great Vintage Les Paul in person, that recordings can't capture the essence and it is therefore that many times people fail to identify a genuine vintage guitar in a recording vs a replica or modern variant. maybe this is true, but i am convinced that most listeners, including engineers couldn't identify whether a genuine U47 was used on a track vs some clone or other similar mic and since these things are only experienced on recordings I dare to say if you can't hear it on a recording then it doesn't matter one bit. YMMV

    BTW, a friend of mine just got a Wagner U47 clone, no idea whether it sounds identical but it sure sounds phenomenal.
     
  8. JJ Blair

    JJ Blair Senior Member

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    Wagner makes a nice clone.

    I can point you to hundreds of great albums that were made without a U47.

    BTW, a lot of 47s don't sound as they should, because they have not been properly maintained, but they are the '57 Chevy of mics. You can get them sounding as they should with the proper parts and knowledge. It's when you cut corners, or let the maintenance slip, that they don't sound as they should.

    My 47s don't get used as much as my 251s or 49s, honestly. But for the applications that I like them on, nothing beats them. They are marvelous mic. And yeah, you can approximate that flavor the same way an R9 can approximate a Burst. But for engineers who know the sound in their head that they want, they know that's the tool they need, the same way a guitar player knows whether it's a Les Paul song or a Strat song.
     
  9. yeti

    yeti Senior Member

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    Not that it matters but the 49 seems to me like a much stronger contender to go the vintage route vs clone. I've heard a few vocals cut with 49s at considerable distances and the reach and intimacy was so outstanding that i wondered if any other mic could match it.
     
  10. JJ Blair

    JJ Blair Senior Member

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    It's my favorite Neumann.
     
  11. LPSGME

    LPSGME Senior Member

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    FYI: I believe the way to remove the 'broadcast mic' limitations imposed on a 49 or 249 is:
    1) C6 (the IRT limitation) can be removed.
    2) The high frequency response can be increased up to about 20k depending on the unit by replacing C4 with a 2 or 4 pF silver mica cap. Just removing it can cause RFI noise.
    3) The low frequency response can be increased by adding 2 M in series with R3 in series, or it can just be removed.

    Then it should be more like a 47 studio mic.
     
  12. JJ Blair

    JJ Blair Senior Member

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    I've never been aware of broadcast limitations being designed in a 49. In fact, my 49s have better HF response than my 47s, and I don't think it was a standard yet in 1951.

    Also, a circuit with an AC701 and BV11 will never sound like a VF14 and BV8, no matter what filters are added or removed.

    The 67 has a high end attenuation for broadcast purposes. It's done through a HPF NFB circuit fed to the tertiary of the transformer. If you change the value of the cap in that HPF, you can lessen the amount of NFB, but removing it completely reveals how harsh sounding the phase shift in the dual backplate design of the K67 can sound, without the filter. The single backplate of the K47 has no such issue, so attenuation was never needed in the design.

    I do not believe that C6 is working as an LPF. My understand was always that it was to limit intermodulation.

    I also don't know what you'd want a lower frequency response for the 49. I find that leaner bass is much more desirable. It's a big reason why the early 49s sound better. In fact, I changed the transformer coupling cap in my M49Bs to .5 µF, to change the resonant frequency between the output cap and transformer, and make the bass leaner.

    If you want better sounding high end, change the grid resistor to 1GΩ. That cleared things up greatly in my experience.
     
  13. LPSGME

    LPSGME Senior Member

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    Discussion about the mod is archived here:

    "The original, first generation M49, as an example, never had any low end- or output attenuation, and only the tiniest amount of high end shelving. But later versions had a severe low cut, (fortunately, removable) a gain reduction of 4dB, and a clearly audible high end cut."

    http://www.neumann.com/forums/view.php?bn=neumann_archive&key=991813548&v=f
     
  14. JJ Blair

    JJ Blair Senior Member

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    Editing for accuracy:

    I stand corrected. My apologies. Later models apparently DID have a LPF, to avoid a pilot tone. Whether or not removing it will make the mic sound like a U47 is highly debatable to me. But broadcast restrictions were never part of the original design, unlike the 67, hence my confusion.

    I was incorrect in the 600pF being for intermodulation. Apparently, it's the 6pF cap that prevents that.

    Anyway, I wanted a leaner low end in my M49b's. I'm not sure that tinkering with trying to give you more low end is desirable, from my perspective.
     
  15. yeti

    yeti Senior Member

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    What frequencies were these filters intended to keep out, CRT Flyback frequency, TV pilot tone, FM radio pilot tone? How steep? What's the cut-off?
     
  16. JJ Blair

    JJ Blair Senior Member

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    19kHz FM stereo pilot tone, apparently. But all LDCs start shelving at 12Khz anyway.
     
  17. LPSGME

    LPSGME Senior Member

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    These comments from an old email from Oliver Archut:

    "Regarding C6 you just remove it, thats a high frequency shunt to meet the IRT specs.. Every shunt gives you -6B per octave and a phase shift of 3 degree per octave..."

    "R5 is the grid leak, 150 M are fine, at low frequencys the impedance of the capsule becomes nearly the same than R5, but replaceing it creates also different problems..."

    "you can remove C6 (this was the IRT limitation) and leave it out of the circuit and replace C4 ith a 2 or 4 pF silver mica cap. the frequency responce goes to about 20k depending on the unit. You can leave out C4 but than you asking for RFI
    oise..."

    "Low frequency, add a 2 M to R3 in series, thats all, or you can remove it...."

    Here's a somewhat technical but informative article about Neumanns ... much more than I care to know. :)
    http://www.vintagewindings.com/gen%20pop/8299543VW8335/ProAudio1/Neumann%20Tube%20Mic%20History.pdf
     
  18. JJ Blair

    JJ Blair Senior Member

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    Interesting. I had completely different conversations about my M49b's with Oliver, who built my power supplies for them, and we spent a lot of time discussing obtaining the sound I wanted.

    I had placed his CT49/1 clones in my M49b's, trying to get the bass to sound lighter, like my early M49, but I wound up not thinking his transformer sounded as good as the original BV11, in my M49b's. I was surprised, because he really nailed the BV8s. His CT49/1's were a little dull, by comparison. It was the only time he did a transformer that I did not think knocked it out of the park. He'd sent me several transformers to either use in my mics or or test for him over the years.

    Interesting that he did not recommend a 1GΩ grid resistor to you. He was a big proponent of those in not just the M49, but also in his own mics, and mods he did on vintage Neumanns. The 1GΩ grid resistor is a pretty standard upgrade for many of the better mic techs in just about any mic.

    Oliver had a thing for silver mica for anything under 10,000 pF, which I never agreed with. In fact, when I replaced his silver mica caps in my CS1s with polystyrene, and replaced the crappy mylar radial transformer coupling caps, the mics sounded exponentially better, and the transient response improved. He was a genius at circuits and transformers, but I never understood his love of cheap passive components. One close friend of his said to me that it was like a game he would play, to see what the cheapest part was he could put in that worked.

    I miss him a great deal. Not just his friendship and sense of humor, but the amount of knowledge we lost with him is irreplaceable.

    C4 is the cap that I was talking about that causes a hi-freq intermodulation if you remove it. Maybe it's a result of the noise he's referring to, but taking it out was an unpleasant listening experience.

    I don't know what he's referring to in terms of 20kHz, though. Even the original M49s start shelving at 12kHz, before that filter was put in.
     
  19. yeti

    yeti Senior Member

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    I'm trying to follow along but am confused about the shelving at 12KHz thing. In cardioid the frequency plot for the M49c shows a HPF with roughly a 40 Hz cut-off (-3dB) and the high freq roll off (-3 dB) at roughly 16K. Therefore the "40-16,000 cycles" spec. There's a bump at 12 KHz and at 14.5KHz it's flat again. The Neumanns I've heard and used don't sound like they are shelving a 12KHz, quite the opposite. I did mention reach before and believe it's quality lies in exactly that bump followed by roll off. Not sure if I'd want to mess with it. There are many mics with a more extended upper HF response that don't sound anywhere near as lively at a distance IMO.
     
  20. JJ Blair

    JJ Blair Senior Member

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    U67 plot:

    [​IMG]

    M49:

    [​IMG]

    U47:

    [​IMG]

    Here's a 251, which anybody will tell you is a brighter mic than a 47 or 49. And 251s have no filter. Straight plate loaded tube to output cap to transformer.

    [​IMG]

    Whether or not they are above 0dB at that point, the shelf on LDCs in cardioid almost always starts around 12kHz, and never recovers. At what point does it go to -60dB? Dunno, because most plots don't even measure past 20kHz in the first place, which would indicate that trying to get 20kHz is a moot point.

    Is it the capsule or the transformer that limits the frequency range? I'm going to guess the capsule, because it's not that hard to make a transformer be somewhat linnear at 20kHz. But I don't know for certain.

    I will tell you this, it is very rare that I've ever boosted 20kHz on a track. In fact, frequently, when I've used a 10 or 12kHz shelf, I will frequently LPF at 15kHz. I don't find the information up there to be terribly musical, and if anything, it usually ends up having something that drives me nuts, particularly on vocals.
     

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