GML op amps

Discussion in 'Electronic Repair Modifications DIY' started by jrmintz, Feb 23, 2004.

  1. jrmintz

    jrmintz Guest

    Hi all,

    I was rummaging around in my cellar and I found a couple of GML 8802 discrete op amps. Apparently this stuff grows down there. Anybody know if these are good for audio? I don't know anything about them.


  2. buttachunk

    buttachunk Guest


    RC they are the discrete opamp found in the majority of Ls stuff...

    they sound great! should be 2520/990 footprint... michael jackson's "thriller" was recorded with gml mic pres-- specifically chosen because of the high speed of this opamp. bruce swedien chose them because "they maintain the original transients" (to paraphrase).

    so here's a rundown of some of the 2520/990 opamps;

    api 2520, hardy 990, jlm--------bipolar transistor
    forssell 992, milinea mm-99-----jfet
    gml, jonathan little (rare!)------high speed bipolar transistor

    be careful with these fast ones-- can oscillate easily and sound like hell when they do. can also torch a power supply if left oscillating for too long...

    if you want to reproduce the L mic pres, i believe it's a simple API-ish circuit with this opamp and beyer dynamic transformers-- the later version was transformerless...


    by the way, thank you ! just got the AD's today ! what can i send you in exchange ??
  3. jrmintz

    jrmintz Guest

    Hi Butta,

    These GMLs aren't API footprint. They're nine-pin (I think) in a flat in-line package about a large postage stamp size. I'll post a picture tomorrow if anyone is interested.
  4. Kev

    Kev Well-Known Member

    Nov 13, 2001
    ... well get down there and start harvesting.

    you guys seem to have have great cellars and dumpsters ! :rolleyes:
  5. buttachunk

    buttachunk Guest

    well, i'd like to see a pic of these then. maybe i'm confusing them with another L disrete opamps-- or maybe they just have different footprints for different applications...


    [ February 23, 2004, 11:49 PM: Message edited by: buttachunk ]
  6. Guest

    Hmmm I really dont know..I mean George Massenburg may have had different layouts for the GML opamps during the more or less 25 years his been making them, but for the GML 83xx preamps..Let me tell you..they are nowhere near the API/John Hardy..etc opamps !!! I think that George once did mention that his opamps were "based" on the API etc.. topologi..(please correct me if wrong)

    The GML pres are all discrete build opamps..both the acturel Gain circuit, and the output driver circuit (which include both conventional transistors and SMD´s)..these are mounted on a real big "main pcb"..there only just about room for 4 of them in a GML 8304 1 unit 19" preamp..with the external GML 8355 +/- 28V powersupply..

    I´d like to see those opamps as well...could be fun to see if any changes were made over the years..

    Kind regards

  7. jrmintz

    jrmintz Guest

    Here's that op amp. Anybody seen them before?


    gmlopamp1.jpg gmlopamp2.jpg
  8. bauman

    bauman Guest

    Nope, never before... what about this green stuff? :D
  9. Viitalahde

    Viitalahde Guest

    ..Seth said he found it from the cellar. :D

    I wonder what's inside! Bring in the hacksaw!

  10. themaster

    themaster Guest

    Well, since we're showing George's early work...

    The Sontec HS-1000:

    (Dead Link Removed)
  11. Guest

    *GGGG*... :D ..Nope never saw these before..quess one can say many things has happend/changed over the years...they look nothing like the current GML opamp generation, and layout..interesting to see.. smile.gif

    Kind regards

  12. bauman

    bauman Guest


    Can't believe my eyes. Brad could you take some more shots? I'll be sooo great to make those HS opamps to my sontec....


  13. edanderson

    edanderson Guest

    yeah, seriously brad, it would be awesome to have any more info on the hs-1000. i'm gonna be having a go at fabio's sontec layout soon, and if we could shoehorn an hs-1000 variant in there it would be fantastic. not to mention that it is basically impossible to even get a replacement opamp from sontec if you actually own their products!

  14. bauman

    bauman Guest

    and looks like you're the only one I know that has it!!!! smile.gif

  15. themaster

    themaster Guest

    I'll really need to get a good dig camera to get some better shots - that's as good as it gets from the camera built into my PDA...

    Maybe I'll run out to Best Buy tonight. hehehe
  16. ssltech

    ssltech Guest


    Just send the Sontec down here and I'l take and post all the pictures for you. -Oh, and don't worry yourself even slightly about anything happening like me 'forgetting' to return it to you or anything like that... ;)

    I promise I'll send it back to you within the decade.


  17. themaster

    themaster Guest

    hehe, yeah, I'll get right on that...

    You know, you guys think API opamps go for a bundle on evilbay, just imagine what this would go for. Somewhere there's a dude with a useless $12k Sontec EQ that would kill his mother for one of these...
  18. Guest

    ohhh Brad,

    I bet-cha`....even more now when nobody seems to manage to get a hold of Mr. Sontec Burgess himself..over the years I´ve heard about plety of good folks looking for this "old" sontec opamp..

    Kind regards

  19. jrmintz

    jrmintz Guest

    Well, apparently I can't count (past four anyway, I am a bass player). There are obviously seven pins. My cats have been playing hockey with the one I took pictures of - should I try to open it up and take pictures? Assuming I can find it.

  20. themaster

    themaster Guest

    OK, I just ordered a new Nikon dig camera, should be here by this weekend. As soon as I get it, I'll get some good shots of the HS-1000 for ya...
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