1. Register NOW and become part of this fantastic knowledge base forum! This message will go away once you have registered.

Auditronics Preamps

Discussion in 'Preamps / Channel Strips' started by tubejay, Sep 5, 2003.

  1. tubejay

    tubejay Guest

    Hi all,

    I just bought a pair of Auditronics Preamp/EQ's from the grandaddy or whatever the hell it's called console. They're already racked up and ready to rock, with a fresh recap. I'm curious if anyone knows much about these? I've heard that putting the John Hardy 990c op-amps will make them sing, but don't have much in the electronics skill department. Does anyone know if upgrading to the 990c op-amp is as easy as popping the old out and soldering the new in?? Anybody have any modification suggestions? I'm looking for very easy modification advice. Also, does anyone have the schematic for these channel strips?

    Thank you again, this forum is fantastic!
  2. redplanet

    redplanet Guest

    I`ve got aschematic for a son of grand console if thats any use to you.This one has 5534s in the circuit and the eq section is an inductor based setup with make up gain.Based on this topology i cant see how the 990 will fit in without serious modification.
  3. Kev

    Kev Well-Known Member

    I've also got some info and a couple of,
    'son of grand' desks.

    don't know much about the grandaddy but there are some pictures of Auditronics consoles at,
    this might help identify exactly which channel strips we are talking about.

    My desk is like this one,
  4. tubejay

    tubejay Guest

    My strips are from the Grandson desk. It's got the three band EQ and the not as cool knobs as the son of grand. The biggest bummer of these is that they don't have the 80Hz eq, it only goes down to 150...which is a bit of a bummer for me!

    Now that we've established which board it is, anybody know anything about it at all??

    Any info would be appreciated.


  5. ggoerss

    ggoerss Guest

    this looks like the channel strip i`ve got.The version i`ve got is a 110B module.It has a jensen input transformer (je110k) as used in the API pre and runs that into a NE5534 with a stepped attenuator for gain control.The eq section appears to be passive and use inductors 3 x torroidal wound jobs.A further 5534 presumeably creates the make up gain and is then fed to another 5534 as the output buffer.These pres as i remember sounded quite nice and the auditronics desks were always highly regarded
  6. tubejay

    tubejay Guest

    Hi George,

    Thanks for the info. That's exactly how these were described to me. Nice Jensen input transformer, with a very cool sounding EQ, and 5534's in the eq and preamp section, and sounding somewhat API-ish.

    So my question is, what's the best replacement to the 5534? Burr Brown?? Something else? When I say drop in, that's exactly what I mean. I don't want to have to add anything else, just replace the 5534's. Apparently they've already been recapped. thumbup.gif
  7. dayvel

    dayvel Guest

    There are two obstacles you may run into with a direct replacement for the 5534.
    1.Custom compensation between pins 5&8 (typically a 22pf cap)
    2.Offset trim between pins 1&8.

    You can try using a Burr-Brown OPA227 (which has no connection to pin 5, eliminating the compensation problem.)
    Most audio circuits from that era didn't use the offset trim pins, so that shouldn't be a problem either; check the circuit board to see if there is a connection to pin 1, if not, you're good to go.
    All in all, I'm not sure it's worth doing, though. The OPA227 has only marginally better noise specs, and the slew rate is not as good as the 5534"s. Try doing one channel and doing a comparison.
  8. Kev

    Kev Well-Known Member

    My desk was originally fitted with LM301's (I think)

    I have replaced most with 5534's. Added IC sockets and caps so a further upgrade could be easy for me.

    However I don't see any need to move from the 5534's. You never know i might look into it in the future.
  9. tubejay

    tubejay Guest

    Has anyone compared the Burr Brown OPA134PA or OPA127 to the 5534? I guess, I just want whatever sounds cool. A little difference in noise doesn't matter at all to me, I'm mainly concerned with good sound. I don't yet have the Auditronics, they are on their way to me as we speak. I'll take a listen, and if they just rock as is...maybe I won't touch them. It would just be cool to get the most out of them for me. Even if the Burr Browns just sound slightly better, it would be worth the $8 upgrade, in my head. Any opinions on which sound the best? Is there any other options I haven't mentioned here?

  10. redplanet

    redplanet Guest

    At the end of the day i think you`ll be hard pushed to better the 5534 in the mic pre part of the circuit.The BB chips may certainly improve the EQ section but that again is subjective.Monty Mcguire has come up with many excellent rationals for chip replacement in consoles, a google search in rec.audio.pro will find them.
  11. adrianh

    adrianh Active Member

    I have the 110B modules.
    If you need a 110B schematic EMAIL ME only.
    My PM box is full.

    All of you guys forget one thing the damn 5534, 5532
    chips sound like poop. They are the worst sounding IC's on the planet. If you ever here a good IC you will know. I am trying to do an upgrade and have not had the time to do it correctly.

    I would like to hear about someone elses results.

    "got to get the 55 family out of my electronics"

    adrianh (at) nceye (dot) net
    remove the spaces and (unspell)
  12. TheBigBeatsInc

    TheBigBeatsInc Active Member

    • you've posted the same topic in several different forum sections. Please try to post this one subject in just one forum location. Thanks!
    Hey all I am looking for as many 501 IME Pres that I can find for a console that I have almost restored! I need 8 more pre amps. Any leads please EMAIL or PM me!!

    Manys Thanks
  13. Kurt Foster

    Kurt Foster Distinguished Member


    Spectra Sonics was the original design of the 501 /502. chect this months Tape Op for a cool article on the history. they discuss the Audiotronics thing too.
    kmetal likes this.
  14. audiokid

    audiokid Staff

    Just found this thread! I always wondered where Spectra Sonics went (I thought it was one word). I owned a really nice 50 watt amp , bought it around 1980. I always thought it was interesting how you'd upgrade the watts by pulling off the front plate and popping a different card for the 100 watt. Terrible for bass.
    Super clean,, good for low level monitoring.

Share This Page