The Opamp thread

Discussion in 'DIY (Do-It-Yourself) Discussions' started by robscix, Jul 4, 2009.

  1. Faber65
    I have a question about the change of the opamp in a DAC.
    According to your experience, how much the opamp swap will affect the SQ?
     
  2. abartels
     
    It depends on VERY many factors.......
     
    To begin with, the weekest chain in the link limits the SQ.
    That said it means that others, with maybe better ears, or better equipment / total chain, CAN hear differences others couldn't.
     
    It's always very difficult to investigate what the weekest component in the chain is, but, to be honest, this is very important.
     
    For example, are you listening on headphones only, or are you listing on a full set in your listening room?
     
    Headphones can be VERY revealing, but listening to a set of very good speakers can reveal more than the best headphone set can, if room accoustics is optimal.
     
     
    I am not avoiding your question, but we need more information to help you.
     
     
    If equipment is optimal, and room accoustics are either, you definitely should hear a performance upgrade from an NE5532/34 for example to a LME49710/20 for example.
    But, that would depend on your system.
     
    If all optimal, I would say the difference could be HUGE, replacing simple and cheap/low cost opamps into high-end ones like the muses, or discrete options like Burson or Dexa,
    yes, it could be HUGE, but, maybe in your set it would be a 5% difference or so, maybe 60%, who can tell.......
     
    So, to answer to your question, switching opamp in a device CAN have a huge SQ increase, but all depends on the device which has to be upgraded, AND the chain it is in,
     
     
    Sorry for this disappointing answer, but that is just the way it is,
     
    Regards,
    Alex
     
    golov17 likes this.
  3. Faber65

    Alex,

    Your reply does a lot of sense to me and it is not disappointing at all.
    I agree 100% with you, and I have experienced on that by swapping opamps on the Burson Lycan, as that was the purpose of that amplifier.
    My question was more specific on replacing the opamp on a DAC.
    Does it make the same difference that it does on the amplifiers?
    I would like to have more opinions or measurements/data on that.

    Cheers
    F.
     
  4. gug42
    Hello,
     
    Did you know a mono equivalent of the muses 8920 ?  (for a gustard H10 and a sb ZxR)
     
    By the way I ve seen that njr start to tallk about a muses03 ... but well can't find any.
     
    thx in advance !
     
  5. abartels
     
    Theoratically it does make the same difference as in an amp. But, as always, our ears tell the truth, and measurements aren't always conclusive.....
     
  6. raoultrifan
     
     
     
    Hello, 
     
    Basically, sound gets "recreated" in following stages:
    - I/V converter (DAC)
    - Low Pass Filter (DAC)
    - Voltage Amplification Stage (amplifier)
    - EQ or Loudness or any sort of sound correction/processing stage (amplifier)
     
    So, any opamps swapped in one of the above stages may alter the sound, more or less. Usually, first thing to do when choosing the right opamp to upgrade with is comparing the specs; also, don't swap low-bandwidth opamps with high-bandwidth ones, because you't know if you have enough decoupling caps installed and also your PCB may not perform admirable too. 
     
    As sometimes best sounding opamp is the one that oscillates more, please check for oscillations at the end of the upgrade. Have a read above:
    - http://www.diyaudio.com/forums/analog-line-level/191389-swapping-op-amps-you-have-checked-see-its-stable-havent-you.html
    - http://www.diyaudio.com/forums/analog-line-level/278732-example-op-amp-oscillation-pics.html
    - http://www.diyaudio.com/forums/solid-state/153368-how-measure-op-amp-oscillation.html
    - http://www.analog.com/media/en/training-seminars/tutorials/MT-101.pdf
     
    zilch0md likes this.
  7. Nurgayan
    In addition to the above, it can be said that minimizing components is the most logical action to improve the quality of the output signal.
     
  8. Faber65

    Thank you and all the others for your replies.
     
  9. Renfield1217

    ​Hi Faber65,
     
    Does anyone know if the Burson V5i's have decoupling caps built into the circuitry of the opamp?
     
    Thanks
     
    Ren
     
  10. raoultrifan
    Hi, 
     
    No caps in there and I don't think there are any opamps with decoupling caps included. Usually, schematic design engineers should take care of these caps, based on calculations and measurements done (depending on the PCB layout and implementation, PSU ripple & noise, external EMI/RFI interferences etc.). So, who designs the equipment should choose the correct cpas value and type.
     
    See you!
     
  11. Renfield1217

    ​Thanks raoultrifan,
     
    And agreed that the card manufacture should designate, but Burson sells their own caps for decoupling.
     
    Ren
     
  12. Minbeo
    Hi, PLZ Help :D i wanna to do obca mod on some NE5534, i look around but unable to find a specific guide for this, which one is obca? which one is buffer mod??? Can somebody shed some light on this, thanks very much!
     
  13. Audio Addict Contributor
    Has anyone compared the Dexa SE with the Sparkos Labs SS3601/02?
     
  14. Minbeo
    Hi guys, i did output bypass mod for my Ne5534 following this guide http://rockgrotto.proboards.com/thread/4716 (minus the class A resistor mod). But when when put them on I/V stage of my dac, sound got terribly distorted. Anyone got idea what happens? tkss
     
  15. rellik
    The opamp chip is overloading the output of your DAC chip as well as overdriving itself (terribly distorted vs distorted). Please include a driver stage and or buffer chip to minimize this effect. Often OP AMps will self bypass their output stages to an extent when properly loaded.

    Some wish to completely define this them selves as per the rockgrotto link yet require special design. Preferably not post DAC. I/V conversion requires the integration of varying minute charge levels ("current") to a locked voltage which can be given a proper reference without destruction.

    Link to: https://www.head-fi.org/f/threads/home-made-iems.430688/page-438#post-13525927 Post #6557 Most OP-amps internal stages work closer to the I of the V side of the I/V conversion. (2-3mA) A serious high input resistance FET loaded into parallel FETS with more leeway(integration room) can handle this.
    The benefit of this is to retain the signature of a favorite op amp/DAC while adding speed. The same function can be used on Op Amp inputs as well.

    Either that or make sure that the output is exactly the same, always, at the same amplitude and loading.
     
    Last edited: Jun 2, 2017
    Minbeo likes this.

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