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Langevin 5116-B

Discussion in 'Electronic Repair Modifications DIY' started by NewYorkDave, Mar 14, 2004.

  1. NewYorkDave

    NewYorkDave Guest

    I've never built a copy of anything; but after scoring five Chicago Transformer BOH-2 (20K push-pull plates to 600/150, +30dBM), I'm considering a Langevin 5116-B. This is an all push-pull circuit using one 12AX7 and one 12BH7. A guy I know tells me that it's one of the best preamps he's ever heard--very "open" sounding--but I'd love to hear comments from anybody here who's either built one or has used an original.
    Schematic
     
  2. rafafredd

    rafafredd Member

    I´ve also heard it and it really sounds great. There´s a studio near my place that has 10 channels of those. This is the only preamps they have, but lots of different mics. I love their recordings.

    Looks very much like the UA 1016.

    Do you know it? I have a schematic for it. Let me know if you do not have it and I´ll post it.
     
  3. Kev

    Kev Well-Known Member

    Looks like a fine DIY project.

    Simple, clean and straight signal path.
    12ax is easy and many to chose from .. can you get 12BH7's easily and a variety of brands ?

    If you can get the trafos or near substitutes then this looks good.
    It just might become a Group DIY project one day.
     
  4. NewYorkDave

    NewYorkDave Guest

    Kev,

    I have a few NOS 12BH7As, and new (eastern bloc) ones are also available at $7-$8 each. Not too bad...

    The original Langevin transformers are mic to 60K, and 20k push-pull to line.

    Rafafredd:
    I'd love to see that UA 1016 schematic. Thanks.
     
  5. cjenrick

    cjenrick Active Member

    I'm afraid that the main reason those units sound great is the Langevin transformers. I think Langevin must have worked for Western Electric at one point, as some of the part numbers I have seen are similar in layout.

    I have also seen some old Langevin's on ebay that look very similar to WE also.

    Get some old WE's for that thing and I bet it will sound great!
    cj
     
  6. rafafredd

    rafafredd Member

    As far as I know, Langevin used transformers that were manufactured by western electric.
     
  7. cjenrick

    cjenrick Active Member

    Ahh, ther ya go!
    Thanks, Rafa!
    When's Carnival!
    And where's my Brazilian girls calander?
     
  8. Antonio_4346

    Antonio_4346 Active Member

    A long time has passed since this thread was active, but perhaps it'll pop up on somebody's radar.

    I just purchased a set of Langevin 5000 series modules: two 5116B Preamps, a 5117 Line amp Module, a 401-B Input Transformer, and the 5208 Power supply.

    I've tracked down schematics for the 5116B and the 5208, which have been extremely helpful, but there are still some loose ends to get tied up before I run AC into this bad boy and try to test it out.

    I'm hoping somebody out there might be able to help me out.

    Below is a general picture of the unit. Notice the modules from left to right are the 5208, 5117, 5116, 401 and 5116.

    Now the rear:

    First off, the Input routing on this sucker is a little bit confusing. There's only one XLR input, which is wired into the first 5116 preamp. Makes sense. Then, the outputs of that preamp are fed into the 410 input transformer. Then, they continue through into the second 5116 preamp. From there, they finally exit out of the unit through the jacks on the front of the unit.

    Why would it be routed this way? Why would there need to be one stage of amplification, followed by transformer, then by another stage or pre-amplification before exiting the unit? Can I simple re-route the inputs and outputs of these units to make them independent from the 401 transformer module, therefore providing two separate channels of mic preamps?

    I can't find the schematics for the 401 or 6117 anywhere, so its difficult to tell whether or not certain characteristics are indeed accurate upon visual inspection (at least for me, somebody with minimal electronics experience). For instance, there's a multi-pin jack on the top of the 401; it very closely resembles a tube socket, though I'm not sure which tube accommodates it, or even if it requires one. The person I bought the unit from seemed to think that was a way of integrating it with the rest of the PA/Comm system of the Naval vessel he seemed to think this thing originated from (aka a multi-pin output).

    This socket is pictured below:

    There are also two sets of pins on the 5116 schematics that are labeled "HTR". I'm unaware of what this is short for, though I do know through my research that the pins labeled "MTR" on the schematic refer to the optional Meter that could have been purchased and installed with these units. These pins, labeled HTR, then route to a very peculiar looking unit, pictured below. I have no idea as to what this is doing. It does seem fairly obvious that each lead set is a send and return to this device, however.

    I suppose my last question is whether or not the 5117 can be converted into a microphone preamp with little to no modifications. And, if so, could it be a dual channel preamp or is this unit designed to be a mono program amplifier?

    Lastly (for now, anyway), I'm still confused as to where I should try and wire in some sort of output potentiometer, so as to regulate the level I send to the tape machine or A/D converters in the studio. Not to mention the fact I could really use some advice for where to insert the input pad, phase switch, and the phantom power supply!

    Here are a few other more detailed photographs, for your reference.

    Any and all help/assistance is greatly appreciated. I've already combed the internet for references and other tools, but the resources are wearing very thin at this juncture.
     
  9. tubegeek

    tubegeek Active Member

    My guess for "HTR" would be the heaters (filaments) for the tubes (valves.) If it's close 6.3 V, either AC or DC, then I'd double down on that bet.

    -j
     
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