Opamps and Modding thread.

Discussion in 'Soundcards, Speakers HiFI & File formats' started by ROBSCIX, Mar 7, 2008.

  1. Tom F

    Tom F Ancient Guru

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    The only way you'll get an opamp to roll off the high end is by using a really slow one, or adding some capacitance into the feedback loop.

    None of those chips you list will roll off at the high end without some extra help in the form of a pole in the feedback loop.

    http://en.wikipedia.org/wiki/Low-pass_filter

    You sure it's not your headphones? I had a listen to some 780s and thought they were super super bright. Nice with the right music, but insanely heavy top end. Do you have any other phones you could try?

    Try an MC1458 - that may do what you're after. Will be very cheap as well :)
     
  2. z3d

    z3d Member

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    wah, so you think that I will hear forever this crying-on-highs signature?
    I don't have other headphones but some IEM's (Brainwavz R1 and stock Sandisk Sansa Clip Zip ones) and a couple of studio monitor speakers with subwoofer (M-Audio BX8 D2+M-Audio SBX10) and with all I feel that highs being too bright or even harsh :bawl:

    So, with neither of those opamps listed forwards I can have a warm sound and roll-off those dazzling highs?

    opa827
    opa2227
    opa2111kp
    lme49860
    lme49720
     
  3. Tom F

    Tom F Ancient Guru

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    I'm not sure to be honest, I've never found there to be much difference between opamps - but maybe have terrible ears.

    If you find things to be too bright, why not add a bit of EQ? That's what it's there for :)

    Of course, it doesn't hurt to try these things. Maybe pick up a couple of the cheaper ones - but I wouldn't get the OPA827 or anything that pricey. It can be very tricky to get them stable - I'm sure some of the differences people report when using these really fast chips are due to them ringing at ultrasonic frequencies.

    Generally when people describe a sound as being 'warmer', it has more distortion. There's a plugin for foobar which does asymmetric clipping - maybe have a play with that, see if adding a tiny bit of second harmonic distortion along with some attenuation at the high end of your EQ gives you that sound you're after :)

    Harshness sounds to me like something is unhappy. You sure nothing's clipping? Does the harshness go away with a more stable chip like an OPA2132 or NE5532?
     
  4. z3d

    z3d Member

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    As for using some EQ, I have to do it on foobar? Is there a plugin for that? Sorry for the dumb question but I never played much with foobar :)
    I ask that because I have ASUS essence software but it's locked when I listen to music by foobar so I can't really use EQ with it.

    About this sentence, what do you mean with "them ringing at ultrasonic frequencies"? Sorry but I couldn't understand.

    Could you please advise me on that foobar plugin? I did some researchs but I couldn't find it, where can I get it?

    With clipping do you mean that some op-amps could have problems with current or voltage and are working badly? I don't think I have this kind of problem cause even using the stock opamps (JRC2114D and LM4562) I get that harsh sound :(

    The only try I can do is using my Ultrasone HFI780 cans, my inear earphone Brainwavz R1 and my monitor speakers+subwoofer setup..I'm not sure but I don't think it's possible that all those have some harsh sound from their own, not coming from my source (essence stx), what do you think about that?
     

  5. Tom F

    Tom F Ancient Guru

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    The foobar EQ is a DSP plugin which you'll need to activate I seem to remember.

    Have a look in Prefs --> Playback --> DSP Manager.

    Interesting distortion plugin:

    http://skipyrich.com/wiki/Foobar2000:Tube_Sound

    A bit of that will give you the warmth you're after, while the EQ will let you tame your high end. Let us know how you get on :)

    The ringing I'm on about is potential oscillation in the opamp's output which is out of our hearing range, which can cause audible distress to the chip, even if we can't hear the oscillation directly.

    http://tangentsoft.net/audio/hs-opamp.html

    Without hearing your setup it's difficult to know where the effects you describe are coming from. Another thing to try would be to see if you still have the harshness with the integrated sound chip. If you do, it's the headphones/speakers - if not, it's your soundcard...again, let us know how you get on!
     
  6. flimbo

    flimbo Master Guru

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    Oooh! I put 3x LME49720HA metal cans back in my Xonar ST. Top stuff! :)
     
    Last edited: Mar 8, 2013
  7. METAVISOR

    METAVISOR Member

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    Asus Xonar DX & dual LME49990 compatibility

    Hello all,

    I`ve been reading a lot about this but there`s something i want to confirm,

    i want to change the stock op-amp of the xonar dx,with dual LME49990 op-amps with this adapter: single to dual op-amp adapter so8 to so8 version http://cimarrontechnology.com/single-to-dualop-ampadapter-so8toso8versionpn031101a.aspx


    can this be done?most of the LME49990 dual op-amps mods are for stx xonar,can dx fully support dual op-amps?

    does this mod needs any cap replacement for properly working?any overheat expected?
    *any equallly alternative to LME49990 for dx?

    i`m ready to go but need to get this clear.

    thanks a lot.
     
    Last edited: Apr 23, 2013
  8. GenClaymore

    GenClaymore Ancient Guru

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    You use a dual op-amp to single op-amp adapter, the dual end is where you place Two LME49990 op-amps on and the single end is what you either place in a dip socket or soldier to the PCB of a sound card. IN your case the DX would require you to soilder it directly on it. What you could do is soider a dip-8 socket on it. So you can easy switch it.
     
  9. METAVISOR

    METAVISOR Member

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    Last edited: Apr 23, 2013
  10. ASLayerAODsk

    ASLayerAODsk Master Guru

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    So I went and tried some Grado's and beyerdynamics....and BD won. :) DT150's @250ohms. :) really good sound out of the box...blows my Sennheiser hd555's outta the water by far..now to start considering the opamp...anyone else have these cans? :) not much to look at..but the sound...and the quality construction..these should be with me for the rest of my life...i usually baby my electronics :)

    and the power conditioner/filter is helping tons as well :) Went with a Monster Power HDP 2500. :) major sound/picture differences after this joined the fray...:)
     

  11. GenClaymore

    GenClaymore Ancient Guru

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    It depends on the op-amp, As for the socket, you would best off with one that is not sticking out from the card too much, so you don't make mistake break it off the adapter or the card.

    What You could do is soilder something like this directly to the DX http://cimarrontechnology.com/othercomponents.aspx , Then place the Two LME 4990's onto this http://cimarrontechnology.com/single-to-dualop-ampadapterpn020302.aspx and install it to the dip-8 socket. That way you can easy take it out if you don't like it, without having to De-solider every thing.

    Also make sure the U on the adapter's and the dip-8 is pointing the same direction as the Dot on the spot on the PCB where the old op-amp was facing. If you don't you damage either the card and or the op-amps.
     
  12. Tom F

    Tom F Ancient Guru

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    Some food for thought here folks:

    http://www.diyaudio.com/forums/analog-line-level/191389-swapping-op-amps-you-have-checked-see-its-stable-havent-you.html

    It's vital you check this - the damage to your kit could be substantial if you're just chucking different chips in all over the place.

     
  13. GenClaymore

    GenClaymore Ancient Guru

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    Only if your not checking to see if it a useable op-amp for audio, and you are just trying Random op-amps off the sites.

    Which why you should use op-amps that been tried and not random models as they are used for different things.
     
  14. Tom F

    Tom F Ancient Guru

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    Any opamp can be usable for audio - in the same way as you could design a circuit in which a 353 or 5532 would be completely unstable.

    It's dangerous to assume that they're all interchangable, just because they have similar pinouts - some (49990 for example) have pretty stringent decoupling requirements. Swapping these around without making the necessary adjustments (or at least checking what's happening) is a recipe for badness and misinformation.

    In that thread the author measures what's happening with an AD797 - which is allegedly one of the best audio opamps out there - when swapped into a circuit originally using a 5532. No way will you hear a 6V @ 1.4MHz oscillation, but your amp will definitely complain!

    Doing this without proper measurements isn't a good idea IMO. You wouldn't try to build a table without using any tools or looking at what you're doing - it's no different with electronics.
     
  15. Radical_53

    Radical_53 Ancient Guru

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    I've started playing around with my opamps again. The reason was that, as of late, I somehow thought that many sounds were coming from the wrong direction.
    Normal stereo music almost sounded as if the singer was standing behind me.

    My Titanium HD has been equipped with 4 Audio-GD Sun opamps. I now swapped the two sitting in the I/V section of the card out for a pair of OPA2111s.
    The positioning has gotten better and there's a nicer soundstage but the sound has also gotten more analytic, maybe even slightly harsh (highs).
    Apart from the soundstage and positioning "speed" is another issue for me, maybe even part of the initial issue. Sometimes, when sounds change rapidly from left to right, it seems like they're coming from both sides simultaneously.

    Now, from people who know the Titanium HD, do you have any recommendations how I might be able to fix my problem or simply improve the situation?
     

  16. ROBSCIX

    ROBSCIX Ancient Guru

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    Yes, but many also note that the AD797 is very unstable in many regards and requires stabalization in some circuits. Personally, I have a background in electronics (analog and digital designs) and I don't haphazardly swap any old opamp in and out of the circuit. The food for thought as you call it is nothing new as far as opamps go and I would hope people understand they are not totally interchangable. You wouldn't hear the oscillation but the opamp would become very hot quite quick. Which can be an easy test for a person without proper test gear or without the know how to measure the current draw.

    Many of the circuits used in audio products are basically generic, some right out of the spec sheets for various components. So in some cases they will fit a wide variety of parts. However, that does not make them completely interchangable. Some opamps need to be decoupled or any number of stabalizing additions some as simple as a resistor on the input pins. It is all part of opamps, if the person wants to get into them, and learn properly.

    I don't think anybody here has ever suggested they are all interchangable because that is just not the case.

    It is a good point to mention though.:) I was considering putting a bit ofinfo or a disclaimer.

    To note, I am not a big fan of the AD797, it is a touchy opamp and I find it does not give a great deal back. However, peoples ears vary and many do like it.
     
    Last edited: May 12, 2013
  17. ROBSCIX

    ROBSCIX Ancient Guru

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    Personally, I would have tried the earth discrete opamps for I/V as they may offer better conversion. Audio-GD recommends that opamps for I/V IIRC.
    The Sun opamps canbe a bit bright in many circumstances-hence the name.
     
  18. Radical_53

    Radical_53 Ancient Guru

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    Thanks for that ;) The first thing I had in mind thinking about the sun was "warmth" :D I'll check their site another time, maybe I missed something there. It's been a while since I checked it.
     
  19. ROBSCIX

    ROBSCIX Ancient Guru

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    They are pretty cheap so you can test different combinations.
     
  20. Radical_53

    Radical_53 Ancient Guru

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    That's true of course, yes. The only problem for me with them is that their "local" retailer for Europe went out of business.
    Ordering stuff from China / overseas works but it takes a long time to deliver and is a pita (customs / shipment) with defective parts.
     

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