FiiO X3 mod - AD8397 to AD8620

  1. ClieOS Contributor
    Someone asked me to post the mod, so I thought I'll make it into an independent thread instead of putting it somewhere inside a X3 discussion.
    Basically the mod is as simple as it gets: open the X3 up, disconnect the battery, desolder the AD8397, solder in the AD8620, and put everything back.
    The goal is to remove the warmness from the AD8397 and replace it with something that sounds more neutral. AD8620 has been one of my personal favourite on portable amp, so it is my first choice. Another candidate will be OPA2209. Both will never be able to match the current output of AD8397 - however, realistically speaking, both already have more than enough output for typical headphone anyway (* = won't be suitable for low impedance, low sensitivity, hard-to-drive 'phone). From experience, OPA2209 probably won't sound as neutral as AD8620, but it should be a good middle point between AD8620 and AD8397 - as alternative for those who find AD8620 too bright to their taste. Another side benefit of the mod will be a likely extended battery life, since both opamps draw less power than AD8397.
    AD8620 on top of X3, just for size reference.
    Be careful on the hold switch (just next to the silver battery). You need to see how it comes off so you will know how to put it back.
    Pull the battery connector out before any mod.
    The stock AD8397, just under the yet-to-solder AD8620. Do check the orientation carefully before desoldering / soldering!
    Done. Put everything back together now. If X3 shows some error on headphone connection, that means you have weak solder joint and you should retouch them with the iron.
    Note: Desoldering SMT is far harder than soldering. If this is your first SMT project, I seriously think you should practice on other thing first. The way I do is pretty much destructive to the original opamp, as I heated and pry a leg at a time, so they either break off or bend out of shape completely. I am sure there are far more elegant and least destructive way of doing it, just search youtube and you should find quite a few of the tutorials. I am however too lazy to bother, as I have some spare AD8397 around and don't need to save this one.
    The result is as I have expected, a much more neutral and detail presentation. I can almost compare it to the X3's line-out + O2. Well worth the effort as this finally brings out the transparency of the player than is somewhat hindered by the AD8397's warmness. Now the new X3 is a proper AK100 killer.
  2. Levanter
    can i send you my X3 to mod too? =D
  3. AmberOzL
    Nicely done. I am not good on that skills I would probably ruin if I try something like that. Too bad for me.
    X3 is already an AK100 killer. Now it even kills it faster [​IMG]
  4. RAFA
    ClieOs you are awesome.
  5. ClieOS Contributor
    There is actually another opamp inside, the AD8692 on the DAC output stage. Upgrading it will further improve headphone-out as well as line-out. I am thinking whether LM4562 will be suitable. But AD8692 is nice enough that I think I will keep it for now, maybe reserves as a future DIY project.
  6. pekingduck
    I also findthat the sound is not as detailed as I would like.... wish I had some DIY skills... [​IMG]
  7. Emospence
    AK100 killer [​IMG]
  8. thegrobe
    Wow this is awesome!

    Thanks for posting this. I have been avidly following the x3 development, and will certainly buy one as soon as it is available in the US. The one thing that is a bit of a worry to me is the "warm" sound signature. I really would prefer something more neutral.

    I have the soldering skills, this mod is a 100% no-brainer. Now just awaiting x3 availability.

    Brilliant! Thanks!
  9. RAFA

    As soon as I get one X3,I will try at least the swap to ad8620, though I like warm sound.

    Wonder how much diffeeence there will be when changing the dac output stage.

    Just a few questions.

    Is the DAC-output stage = the DAC buffer?

    Is it a single ic?

    Thanks rafa :)
  10. ClieOS Contributor
    It is a dual channel opamp. Yes and no on the buffer - yes that it does act like a buffer; but no that it isn't there as buffer. WM8740 only outputs differential signal (positive+negative for both left and right) so you need an opamp to convert it to single ended signal (left/right/ground).
  11. RAFA
    Thanks for the info. I can prepare myself a little.
  12. ClieOS Contributor
    I abandon the idea of LM4562 for AD8692. Need to find a rail-to-rail, low power, low noise opamp for the job, and LM4562 isn't rail-to-rail. The search continues...
  13. Armaegis
    Heh, so now who's going to be adventurous and try to bend and fit this in with two OPA627's? [​IMG]
  14. AmberOzL
    ClieOS, at your signature it says almost time to leave with very small letters. Does it mean soon you will close head-fi account? I hope not [​IMG]
  15. phantompersona
    Can I send a x3 for you to mod?I'll gladly pay you :D

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