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DIY Preamp for Ribbon Mikes?

Discussion in 'Microphones' started by Keith Dayer, May 22, 2002.

  1. Keith Dayer

    Keith Dayer Guest

    Being a newbie, a tinkerer, and one who is interested in recreating "that sound" from the early 60's obtained in some of those great jazz recordings, I have obtained my first really decent microphone; a Stephen Sank modified B&O. It has the sound I want, but the mixer boards I use have too much hiss and not enough gain. As others have noted you need quiet gain in the area of 65dB plus to get good level out of a ribbon, especially if placing in an ambient x-y position. I intend to record live jazz using minimal miking. Can any one suggest a DIY circuit topology that might give me some pre-gain that I might put out there next to the mike? Any thoughts short of spending a fortune on World class dedicated pres? Do I need a tranny if I put the pre near the mike? I see lots of circuits out there, tube, class A, Neve clones, but I was wondering what other ribbon mike users have learned, trying do do it on the cheap.
     
  2. RecorderMan

    RecorderMan Distinguished Member

    Joined:
    Mar 28, 2001
    I'd recommend getting aUniversal Audio 2-610 Tube pre amp. It has an impedence matching circuit specifically for ribbons. and is a replica of Bill Putnam's Pre's, which were used on alot of records of that era. Around $2k, for a little over half that (I believe) you can get the mono version.
    Great pre's IMO
     
  3. knightfly

    knightfly Active Member

    Joined:
    Jan 18, 2002
    Hey Keith - On a similar note, I saw a Royer ad a couple of days ago where they've released a new ribbon (122, I think) that is a 121 with a phantom pre, I think they claimed 15db more signal level - sounded like a good move to me.

    Also, ""If it measures good and sounds bad,it IS bad. But if it measures bad and sounds good, you've measured the wrong thing." Daniel von Recklinghausen, retired design engineer at H.H. Scott" - I don't know how long you talked to Danny, but if it was for more than 5 minutes you probably realize just what an amazing person he is. My wife and I both had the pleasure of working with him briefly at H.H. Scott in 1966-67, and other than the purchase of my first Webcor tape recorder I think Danny was the single biggest influence on my wanting to know always more about sound. We lost touch shortly after, so it was a really pleasant "blast from the past" to hear that he was still kicking in 1999. Your signature block made my day, thank you... Steve
     
  4. Keith Dayer

    Keith Dayer Guest

    Several things to respond to folks. First, I'd REALLY like to see some info about a "phanthom preamp device". When you think about it, it would serve several useful purposes with low output mikes like ribbons:

    1) Provides early gain (up near the mike where it belongs. We all know what that can do for noise and cable issues.
    2) Makes it possible to use mixers which are reasonably quiet and clean if their input gain trim isn't pushed to the top. May explain in part why condensers are as popular as they are. More output.
    3) Most mixers have phanthom supplies which when switched on, are available at EVERY mike input, whether you want it or not. Although some vintage ribbon mikes tolerate this, not all do. With a phanthom preamp in line, The phanthom supply not only can power it remotely, but the preamp can effectively isolate the ribbon mike from this DC voltage, allowing the phanthom supply to power any consenders as well.
    4) Adding gain up near the mike would serve the same purpose as a preamp found in condensers, possibly eliminating the need for a transformer at the phanthom preamp's input to reduce noise, because the distances traveled are very short.
    I was thinking This preamp would have perhaps as much as 30dB of "pre-gain" before the mike preamp, but it could also have more gain and run closer to a line level. Of course, any tube design may need its own power supply, making it more of a stand alone.

    Also, I would LOVE to buy a real nice two channel tube preamp. MY wallet, unfortunately is too challenged and since I am at heart a hobbyist/DIY-er, finding a suitable design and making a couple prototypes makes $en$e to me. That's why I'd rather build it.

    Finally, DVR is indeed one of those individuals who can indeed make you stop and think about how we started out pursuing better audio and got sidetracked about 40 years ago, when the audio horsepower and gadget marketing got out of hand. He is a gentleman of the highest order, and we collectively owe him a great deal to the success of the art. His statement, which I quoted, reflects how I have often thought in my pursuits as a broadcast engineer. I am happy to say, Danny is still out there, lecturing overseas at various audio engineering society meetings, still tinkering in his basement, very active - and he is in his 80's! The 4 hours I spent with him I will never forget. Much of the entire interview is published on the vintage H.H.Scott website.

    Anyway, I'm open for suggestions on an available design. I was kinda thinking maybe a discrete class A "Neve-ish" front end. Perhaps I should go to that DIY group and ask....

    Cheers,

    Keith
     
  5. Kev

    Kev Well-Known Member

    Joined:
    Nov 13, 2001
    A friend of mine used my SSM2017 Mic-pre on near minimum gain and fed that into a combination of Mic-Pres , Avalon, Amek, even the Neve 51 series desk. Strings mainly, the movie was Elizabeth.

    Group DIY has some 1272 info.
    ..... try JLM Audio
    and John Klett - obseletes.
     
  6. mig27

    mig27 Active Member

    Joined:
    Feb 15, 2002
    Location:
    Berlin, Germany
    off topic, since not DIY...
    Let me recommend you a vintage telefunken V276 mic pre.
    They're solid state, very clean, dark and full sounding. 76dB gain should be largely enough for your B&O's. Plus, they won't break the bank - you usually can find them for around $300.00 at eBay.
    best of luck...

    Michael
     
  7. Bear's Gone Fission

    Bear's Gone Fission Active Member

    Joined:
    Jan 4, 2001
    Look at the schematics at the Jensen Transformers website. The Dual Servo topology (990 or IC) should give high quality clean gain if you can do a good layout. I don't know that I could. The Cascode tube design should be pretty gainy if you want to do tubes.

    Bear
     
  8. Kev

    Kev Well-Known Member

    Joined:
    Nov 13, 2001
    On the subject of the 990 ...

    Joe Malone of JLM says he will soon have his 990 available to be purchased from the web site. He has sent many of these around the world.

    http://www.jlmaudio.com
     

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