Opamps and Modding thread.

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

  1. dcvolt

    dcvolt Member

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    The visit to a friend's house to bench prelude -x meridian and cd player
    turned out to a disaster my pc was refusing to boot:bang: in his house.
    all i can say is that meridian was very close to the cd player
    here are some pics

    [​IMG]

    My buddy mesuring the rooms acoustics

    [​IMG]

    Preaty bad in fact from 3k to 20k he looses 10 db 0_0

    [​IMG]

    X-Meridian with power supply in htpc 4 x 627
     
  2. dcvolt

    dcvolt Member

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    verdict

    By having a reference of a Modded cd played and comparing it with the
    x- meridian . i must addmit that the meridian with stock caps plays music better than prelude with better caps, and yes my prelude with the new caps was playing overall better than before i change them.
    Both cards with power supply ofc and same opamps.
    On the other hand prelude can play games like a champ :D
    I'm very satisfied with dts moovies too .
    My buddy claims that getting an external dac under 400 euros like dacmajic will not improuve my sound .
    Getting a good external dac for 3000 euro is not an option im afraid .
     
  3. wlw_wl

    wlw_wl Master Guru

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    Isn't that transofrmer so close to the GPU causing interference? That's one big EMI source so close to the card...
     
  4. dcvolt

    dcvolt Member

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    nop no interference at all in either sound or image ....
     

  5. ROBSCIX

    ROBSCIX Ancient Guru

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    I find the 637 an upgrade to the 627 but it depends on what you like and the circuit.
    Ihad another idea for a way to add external power supply to a card that draws power from the slot. Great stuff though for sure!

    I have been thinking of doing some new mods on some of my cards.

    You should try out my dual LME49710HA module. The single LME49720HA's are also nice but I prefer the dual one.
    There are some pics back a few pages....here I will post it again.

    [​IMG]
     
  6. ROBSCIX

    ROBSCIX Ancient Guru

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    To note, you peaked my interest for modding the X-Meridian 7.1.

    A great opamp for bass is the OPA2227. This may be one you might want to check out.
     
  7. dcvolt

    dcvolt Member

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    woot some nice looking opamps there
    they should be in the 250 euro range though ):
     
  8. NapalmV5

    NapalmV5 Member Guru

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    LME49720HA you say Rob hey!?! ok ill givem a try.. i mean getting 6x LME49720HA for halo xt :)

    damn! more $ wasted.. i mean invested! :D
     
  9. ROBSCIX

    ROBSCIX Ancient Guru

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    No. These aren't that pricey. The smalle signal module is a LME49720HA and the dual metal can verison is a LME49710HA module.
     
  10. ROBSCIX

    ROBSCIX Ancient Guru

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    You have PM:)
     

  11. angershark

    angershark Master Guru

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    Just curious has anyone here experimented with class-A opamp biasing with resistor or JFET?
     
  12. ROBSCIX

    ROBSCIX Ancient Guru

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    Yes, I have been thinking about it and may even build some custom adapters biasing. I have been considering biasing:
    LME49710
    OPA827
    OPA627
    OPA132

    Ther are others I have been considering but these are the ones I am interested in biasing right now. I just have to wait until I get my new parts shipment. I will post my results when I get them tested...
     
  13. angershark

    angershark Master Guru

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    From what I understand they run quite hot when biased to run class-A all the time. I thought about trying it myself but taht would require soldering to the back of my card, which I'm hesitant to do heh.
     
  14. ROBSCIX

    ROBSCIX Ancient Guru

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    Well from the front opamps you could use a module similar to my LME49710HA module.
    It was said you cannot do this procedure on dual channel opamps chips. I have yet to verify that part though.
    The LME49710HA module is TWO single channel opamps and work when biased to class A -or so I have been told.
    As for heat, yes Class A amplifier have always been known to run hot and not very power efficient.
    I have talked with others though and they say the biased opamps don't run too hot. I guess it depends on the circuit and opamps unit. I will be trying it sooner or later so I will post my results when done.
    I will be talking with a expert on this idea and get all the details I can about the mod.
     
  15. angershark

    angershark Master Guru

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    I was wondering about that, seems to me it would work but I'm not certain.

    I await your results :)
     

  16. riiaku

    riiaku Active Member

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    purchasing the opamp

    When I buy the Opamp from lets say, Newark, does it include the adaptor that I need to install it with? I saw on auzentechs website for the OP637SM + adaptor, but I dont want to buy it from them because its a rip off. So what is the model of that adaptor so I can buy it through newark or someone else?
    http://www.newark.com/texas-instrum...ier-op-amp-ic/dp/75C5111?CMP=AFC-JY6146109556

    Can someone please help?
     
  17. ROBSCIX

    ROBSCIX Ancient Guru

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    Those adapters, the dual TO-99 are not readily available.
     
  18. riiaku

    riiaku Active Member

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    Last edited: Oct 25, 2009
  19. riiaku

    riiaku Active Member

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    If I buy the OP637SM from Newark then will it come with the adaptor so I can install it on my Forte when i get it?

    ROBSCIX where did you buy your OP637SM? Auzentech or digikey?
     
  20. Famous627

    Famous627 Master Guru

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    You will need something like this but since that opamp is single channel you might have to use your imagination like this.

    If I were to do this again I would just make a wiring harness out of dip8 sockets and use the to99 adapters for the single channel opamps. This would reduce the amount of white knuckled soldering and give you an easy way to swap out single channel opamps.
     

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