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SA9227 PCM5102A Asynchronous 32bit 384Khz USB DAC

Discussion in 'DACs' started by mroboto, Aug 31, 2018.

  1. mroboto

    mroboto Super Member

    Messages:
    1,462
    I already have of two of these DACs, just ordered the third.

    I slightly modify them (swapping and adding few parts) for 2 reason,

    1st. If you own this DAC and don't add filtering capacitors, you may have experienced some freezing problems, the USB SA9227 chip gets hot and stop transmitting signal, the issue is fixed for me by adding small and low cost capacitors.

    2nd. it sounds great (better) once modified, must hear to believe, for a DAC in this price range (Including the price of the additional parts).

    Original (Click on the link at the right of "Doccument joint" to see full size):
    https://www.cjoint.com/c/HAfcRveUSlt

    Modded:
    https://www.cjoint.com/c/HEieOQLFqc6

    With two Wima MKS2 10uf 50V as output coupling capacitors.

    One 4.7uf 50V Multilayer ceramic capacitor on the regulator on the left in front of the SA9227 USB receiver chip.

    One 10uf 50V Multilayer ceramic capacitor on the regulator on the right in front of the PCM5102A DAC chip.

    Rear:
    https://www.cjoint.com/c/HEieQ0Hvq76

    And one 2.2uf 50V Multilayer ceramic capacitor on the USB 5V input.


    The SA9227 Windows driver can be found here:
    https://support.hifimediy.com/suppo...vitech-sa9227-uda38pro-uda18-uh1-uh1-digital-

    The DAC support up to 24bit 96Khz without the driver, or without restarting Windows,

    But to support higher resolutions, the driver is required, and you have to start a Windows session after the DAC is plugged in the PC (If you unplug and plug it back, it will be recognized as FS Audio USB instead of HD USB Audio).


    If you look for a low cost but quite good sounding USB DAC, that will last forever without the need to restore anything (no electrolytig capacotors to replace, ever), this is a good recommendation, but not if you have no intentions to mod it, at least, add filtering capacitors to make it reliable.

    If you still having issues after upgrades, (not me), but the SA9227 chip is still warm, you can also add a 10x10x10mm heatsink on the SA9227 chip to keep it cool.


    Note: Some may prefer to remove the output coupling capacitors and have DC coupled output, it's possible with this DAC chip, but I prefer to be safe for my tube amps and speakers using the Wima capacitors for output coupling.
     
    Last edited: Sep 1, 2018

     

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  2. mroboto

    mroboto Super Member

    Messages:
    1,462
    I replaced the 2.2uf that I previously added to the 5V DC input for a 4.7uf , and added a second 10uf for a total of 20uf for the PCM5102A DAC chip regulator (the regulator on the right), they work and sound very fine.
     
  3. cpt_paranoia

    cpt_paranoia Well-Known Member

    Messages:
    813
    It does look like the voltage regulators don't have the usual, recommended decoupling caps on input and output. I'd use surface mount components, close to the pins. But I have access to a professional rework station, and access to such components.

    Identify the regulator devices. Read the application note. Add the recommended decoupling components.
     
  4. JoeESP9

    JoeESP9 ESL's & tubes since 83

    Messages:
    16,520
    Location:
    Philadelphia PA
    I don't understand why anyone would buy a product that needs to be modified to work properly.:dunno:

    To buy a second and/or third makes no sense to me.

    I have no problem with modifying something to make it sound/work better. However, modifying it to make it work properly out of the box is a gigantic red flag for me.
     
    Last edited: Oct 1, 2018
    E.Auer likes this.
  5. mroboto

    mroboto Super Member

    Messages:
    1,462
    Do you own this DAC or tell this only by pictures I posted ?

    It uses SMD capacitors on it, not sure if it use decoupling before the regulators, but sure there is some after.

    The results of the simple mods I done are very good, I look no further.

    They have designed this DAC starting from the SA9027 ES9023 design that I know about, this one is nearly identical except for the chips it uses, and the first DAC had no problem, probably they thought this one will be perfect too, but no, they have not tested this design extensively.

    The SA9227 chip is sensitive to noise in the power supply, and since the chip is sensitive to noise, it overheats, some DACs that uses this chip uses heatsink on it, but they didn't added one, with proper supply, it heats less, and work as it should work.

    I first bought one to try, modded it and was impressed by the results, bought another for a second system (New portable computer for my bedroom), I use the first one in my main system when I don't use my TubeDAC-11, I like to change sometimes, and since they work fine, sounds great, and are cheap, I bought a third one for the future, I have 4 computers in total.

    The last mods I done taked it to an higher level.
     
    Last edited: Oct 1, 2018
  6. JoeESP9

    JoeESP9 ESL's & tubes since 83

    Messages:
    16,520
    Location:
    Philadelphia PA
    I too own and use multiple computers (5 total, 3 laptops and two desktops). Unlike many I have one main stereo/AV system. Never in life would I buy or otherwise acquire any device that needs to be modified to work properly. I'm all for modifying something to make it sound better. Modifying it to make it work properly doesn't work for me.
     
    Last edited: Oct 1, 2018

     

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  7. mroboto

    mroboto Super Member

    Messages:
    1,462
    I don't try to sell you this DAC, just inform about my discoveries.

    This is a desing flaw that is easily corrected, I understanded this quickly with my first.

    And since a Multilayer ceramic capacitor will last forever, this flaw will never have to be corrected again, and the sound improved a lot by the way.
     
    Last edited: Oct 1, 2018
  8. mroboto

    mroboto Super Member

    Messages:
    1,462
    One thing I don't like with this DAC on a laptop with Windows 7, is that the screen won't shut down at all when you set it to shut down after 15 minutes in power management.

    But on Windows 10 , it shut down as it should.
     
  9. mroboto

    mroboto Super Member

    Messages:
    1,462
    Sometimes, he didn't freeze in a day, and he freezes twice the day after, it was random.

    Had to unplug and replug it.

    And If I wanted it to recognize frequencies over 96Khz again, I had to restart computer so it is recognized as HD Audio not FS Audio.
     
  10. cpt_paranoia

    cpt_paranoia Well-Known Member

    Messages:
    813
    Just looking at the pictures.

    U1 and U3 will be the linear voltage regulators. It is normal to place decoupling capacitors as close to the pins as possible. It's clear that there are no capacitors near the pins of those devices, even though there is space to do so.

    They are SO-223 package devices. Probably something like an LM2937 LDO regulator*. Here's the TI datasheet, which includes recommended decoupling (100nF input, 10uF output), and a recommended layout (figure 27, p18), with decoupling right next to the pins. It's also worth noting the ESR spec on the output capacitor (10mR to 3R), required to keep the regulator stable; you can't just stick any old capacitor on the output.

    http://www.ti.com/lit/ds/symlink/lm2937.pdf

    * I can't see the markings, so I can't confirm exactly what part they are.
     
    Last edited: Oct 1, 2018
  11. mroboto

    mroboto Super Member

    Messages:
    1,462
    They both are AMS1117 regulators.

    Adding a multilayer ceramic before, (4.7uf at the 5V input) , and on the output pins (4.7uf on the left SA9227 regulator) (and 20uf on the right PCM5102A regulator) is, I think, a good choice, and I understand why it sounds better.

    USB standard specify 10uf max at a specified "?" impedance for current surge, I think I do not exaggerate too much with what I done.
     
    Last edited: Oct 1, 2018

     

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  12. mroboto

    mroboto Super Member

    Messages:
    1,462
    I made a clean install of Windows 10 build 1809 on my laptop this morning, and now the screen won't turn off, exactly as Windows 7.

    As soon as the DAC is connected to the USB port, the screen won't turn off by any mean when a Windows session is started.

    I don't know how I did this spring on build 1803 to make this work properly, I don't know what is to do or not to do, what's the trick ?

    I searched the internet in the past, and there was a command to show what devices wake up the system, and you can configure by another command but this command shows nothing, no device wake up the system, so I'm lost.
     

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