DACs: Improve your USB (break out PCI USB card with Unison)

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by purr1n, Jan 1, 2022.

  1. purr1n

    purr1n Desire for betterer is endless.

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    Using computer USB with DACs has been a dilemma for audiophiles. For many years, USB was thought to sound worse than SPDIF or AES from a good transport. I went down this rabbit hole myself years ago: https://www.changstar.com/www.changstar.com/index.php/topic,925.0.html. Other members have gone down similar rabbit holes with excessively long chains such as Mutec/Dante/Whatever. Done correctly by someone who is a good audiophile chef, the results can be superb. However, there is no question that these approaches are excessive and actually kind of dumb, in that they increase our chances of dying as bitter lonely old men.

    One thing which I don't people really understood is that USB is a two way street. There's a lot of obsession of what is on the receiving end, be it XMOS, Cmedia, Unison, Ti, longSchlong and other boutique brands. However, many folks seem to ignore what's on the transmitting end. I've all all sorts of results with different sources. My old Sony VAIO laptop had a dedicated USB port which sounded better than the other ports which it was isolated from. The USB on cheap Dell laptops I had all sounded like ass compared to my gaming tower PCs. Heck, even different operating systems sounded different, with Linux and MacOS sounding better than Windows 7. (Windows 10 actually sounds pretty good). There could be reasons for this with respect to how the operating systems send or rearrange USB packets.

    Anyway, this came to mind because @rlow mentioned that his boutique Sotm AIO source sounded better using Unison than SPDIF/AES from pi2AES. The latter being a standard among many members, mainly for it's easy of use for streaming (once properly set up). @rlow's post comparing three different source transports is here: https://www.superbestaudiofriends.o...sports-shootout-with-unison-usb-and-aes.8810/

    So this got me thinking. I know there are many fans of the sound of Unison USB on the Schiit DACs here. However, I've always taken a liking to a good SPDIF/AES source to the Yggdrasil DAC over any USB including Unison. Unison to my ears has been too tubey, too smooth, slightly glossing over stuff. No doubt it's better than the older Gen 5 from Schiit, but perhaps too much into the other direction?

    This is when I realized that I picked up this PCI USB card years ago intending to try it out. I forgot about it until recently when I found in a box of old that I had just unpacked. This card is still available from Amazon, although the brand of it has changed. https://www.amazon.com/BEYIMEI-Expansion-Connector-Suitable-Linux(2X/dp/B08DFBCSH3/

    5F4A0068.JPG

    The chipset is Renesas:

    upload_2022-1-1_13-48-31.png

    So I was curious if this would sound better than the USB 3.0 and 3.1 outputs from the back of my motherboard. That if I would have a similar experience to @rlow in having something better sounding than the piAES AES output, that is being able to reach the fuller potential of Unison.
     
  2. purr1n

    purr1n Desire for betterer is endless.

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    The answer is a resounding yes. The card has two buses, so I was careful to dedicate one USB bus to the Yggdrasil Unison with nothing else connected to it. The sound isn't different either. It's better, like a better Unison. Not all out wet, tubey, and smoothed over. The sound retains many of the old Unison's qualities, but now not glossed over, with the focus and microdetail or the piAES's AES output.

    Does this render the pi2AES redundant? Nope, not at all. The pi2AES remains because it's one of the most cost-efficient streamers around (provided one is willing to put in some elbow grease) and I've got two in the house. However, for those who have a tower PC with extra PCI slots, this $20 board could take you to the next level of what Unison is capable by bypassing the stock motherboard USB and allowing us to isolate a bus for USB audio purposes.

    Note that the card requires its own power from the PC power supply. The neurotic can explore avenues such as a dedicated 5V LPS instead of the 5V line from the PC supply, which I know are not regulated well. FWIW, I am running a high-end PC power supply, the AX860i.
     
    Last edited: Jan 2, 2022
  3. purr1n

    purr1n Desire for betterer is endless.

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    I was curious to see if there where any measurements that may show if there are any differences between the Renesas USB and motherboard USB 3.0 (ancient Gigabyte AB350 Gaming), so I fired up the AP-555.

    I used ARTA to generate a JTEST signal via Unison into the Schiit Yggdrasil LIM DAC. Measurements were taken at the balanced outputs.

    Yggdrasil LIM BAL outputs
    44.1kHz JTEST via Gigabyte AB350 Gaming motherboard USB 3.0
    jtest mobo 3,0 USB.jpg

    Yggdrasil LIM BAL outputs
    44.1kHz JTEST via Renesas PCI card USB
    jtest mobo ext USB.jpg

    Nope. I don't see any difference. In the past when I didn't see a difference, I just didn't bother posting it. However, I think it's important that I start posting stuff, even when there isn't a difference. There are two explanations here:
    1. I imagined the differences, they are all in my head. I should conduct a double-blind test to verify.
    2. The perceived differences are there, but these aren't the right measurements.
    I dunno. Conducting a blind test is a royal PIA. Since this card cost me only $20, and I needed more USB ports anyway, I'll keep it and continue to believe that this PC with the card provides me with the best source for the Yggdrasil DAC do far.

    Now what would be interesting is for me to try it on DACs using other USB receivers.
     
    Last edited: Jan 1, 2022
  4. k4rstar

    k4rstar Britney fan club president

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    I'm glad you're covering this topic. I tried a similar experiment over a year ago. I've been using a 2008 Mac Pro which has the best-sounding USB ports out of any machine I've tried. makes sense as this machine was a studio standard during it's production life.

    I purchased a Sonnet card for cheap off ebay: https://www.sonnettech.com/product/legacyproducts/allegro_express_usb.html
    and installed it in the Mac Pro. the sound was noticeably worse than the motherboard ports. In this case I think the dedicated 5V was not worth the trade-off of a longer internal signal path through the PCI bus, and the regular ports on the Mac were just better.

    I still have the card I'll repeat the experiment with a normal Windows PC and also hook up a cheap LPS and report back. It should be noted that PCIe is worse than PCI for audio applications and most modern motherboards do not have legacy PCI slots anymore. This became clear to me in 2018 or so when we were comparing Lynx and RME sound cards with S/PDIF out.

    BTW, the 800 euro JCAT 'audiophile' usb card is just a OEM card using the same USB controller as the $20 amazon USB cards, with some fancier regulators and a DC input jack for an external PSU
    https://jcat.eu/product/usb-card-xe/
     
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  5. AllanMarcus

    AllanMarcus Friend

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    Interesting. Do you think the perceived goodness is a result of a dedicated USB bus for the audio output, or that cad specifically? Maybe the improvement comes from the power not being routed through the MB, as it is with the on-board USB ports.
     
  6. Garns

    Garns Friend

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    It's definitely a crapshoot, some mobo USB ports are better than expansion cards, some are worse, but it's a pretty cheap experiment to try. With cheap SoC Atom mobos I didn't find a generic USB card which sounded better than the best of the on board ports.

    Another point to note is that Yggdrasil is very sensitive to HF hash on the ground plane. Putting masking tape over the outer metal shell of the USB B connector breaks the ground connection from the PC to Yggdrasil which I found reduces sibilance and digitus quite noticeably (though no change in focus). If you like the effect you can make up or get made up (eg by Ghent Audio) a cheap cable with the shield disconnected at the USB B end.
     
  7. econaut

    econaut Almost "Made"

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    In my main two channel system I switched from

    Windows PC -> Unison USB -> Yggdrasil A2

    to

    Windows PC -> Pi2AES -> AES -> Yggdrasil A2

    This was a step up, especially in terms of clarity and less listening fatique.

    But the real game changer for me happened, when I switched the Pi2AES for the SotM sMS-200ultra Neo:

    Windows PC -> SotM sMS-200ultra Neo -> Unison USB -> Yggdrasil A2

    WOW! Enter depth galore and for the first time I understood the term blackground that I was reading here for several years. Before I had just understood 'blackground' in theory, but had no clue how more or less 'blackground' would sound.

    I got the SotM used and I just got it out of curiosity. I actually wondered if I would hear any difference at all.

    Boy, was I surprised. You can hear the difference in seconds. No critical listening necessary at all.

    A litle anecdote: Gushing I had to show my girfriend the difference. When I switched back to the Pi2AES she was shaking her head, so bad it sounded in direct comparison.

    I figure that the difference is bigger with speakers than with headphones (soundstage not headstage).

    Many thanks again to @rlow for his tale of three transports. Elevated my music listening experience by several margins! :)
     
  8. purr1n

    purr1n Desire for betterer is endless.

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    I think it's both. The card is cheap enough so I would encourage further testing and evaluation among yourselves. I don't have as much time these days. I'm sure you guys have noticed, I prefer to present half-baked ideas and have others pursue solutions. It warms my heart that the UK guy is offering an HD6xx mass loading and swappable foam solution: https://www.superbestaudiofriends.o...hd650-mod-measurements-and-impressions.11801/ or Grado is now offering their SR325X and SR225X with F-cushions.

    That being said, when I shared the bus with a USB ethernet dongle, the sound quality (again Unison to Yggdrasil LIM) was not as good when the bus was not shared. However, it was still better than the AES outputs of pi2AES. I should make clear that the differences were small, but still discernible in the overall scheme of things. This of course could also mean that the differences are huge to discerning audiophiles.

    Not picking on this one; but I would be lying if I didn't want to expose these kinds of overpriced products. Perhaps @atomicbob could design an inductor based noise nuke for this $20 card? Would be curious of the results.

    For sure. It's definitely a crapshoot. Lots of variables, too many variables. If this were a $200 solution, I would not have written about it. For $20, it's worth trying, especially if one needs more USB ports. There's no guarantee that a different PCI board would sound better than a motherboard USB. Finally, I think Windows 10 has something to do with it.

    One could also build a custom cable. I made for use with the Empirical Audio Off-Ramp 5 back in the day since the USB power didn't need to come from the transmitted.

    +1
     
    Last edited: Jan 1, 2022
  9. internethandle

    internethandle Almost "Made"

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    FWIW, that nuts ORFAS 20k USD server from Taiko Audio until recently (now it’s some custom OCXO card) used its on board mobo audio for USB out because the designer claimed it sounded best. Some folks on other forums figured out the dual CPU Xeon ASUS board they were using has a ASMedia 3142 for its controller chip, which you can find in PCIe cards for about as cheap as the Renesas cards. The 800 buck JCAT card uses ASMedia as well, I think (although not the cheaper “Femto” card, it has a Renesas chip).
     
  10. econaut

    econaut Almost "Made"

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    Does anyone know if Unison USB needs 5V on the USB connection for handshake or communication?

    Just found this USB card and many raving user reviews.

    One can easily switch off power delivery on the USB and let the DAC just use its own PSU. The USB bridge chip from Texas Instruments opens up independent data channel for USB audio stream. It helps signal bypass the USB controller integrated in the motherboard, avoiding the sharing of data channels with other USB devices in the computer.

    So if Unison only uses data and not power this might be worth a try. Talking only about self powered Unison DACs, of course.

    Above quote from here:

     
    Last edited: Jan 1, 2022
  11. purr1n

    purr1n Desire for betterer is endless.

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    If only the handshake is needed, it's not hard to build a custom cable with a switch.
     
  12. econaut

    econaut Almost "Made"

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    Just found the answer by @Garns in a post from 2019:

     
  13. Beefy

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    I'm not sure how it's implemented in commercial DACs, but I researched lots of different DIY interfaces recently.

    By default they almost exclusively draw power from the USB connection to power the receiver. Then, the decoded digital signal is usually sent through galvanic isolators that are powered by the DACs internal power supply. This keeps power supply and ground noise from the computer out of the DAC.

    If the receiver is powered by the DACs internal power supply, that can actually create more problems. This is because you end up tying your DACs power supply ground to the USB data ground. This is bad, no matter how clean the new power line is. The only way to avoid this is to have an entirely separate power supply just for the USB receiver, isolated from the DACs power supply, which is just nuts from a design point of view.

    So, I'm not sure what my point here is? Maybe other than cutting the USB power from the computer might not always be the best solution. Especially if your USB interface has galvanic isolation.
     
  14. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    is this a PI2AES versus SoTM comparison or an Yggdrasil USB versus AES comparison? Does the SoTM have AES output?

    And yes, I am not unbiased. But I wonder if the results were fair.
     
  15. econaut

    econaut Almost "Made"

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    No, the SotM only has an USB out.

    I don't judge if this is fair. Mind also the huge difference in price. Also the SotM was run by a LPSU and the Pi2AES was not.

    So in total one has to say: SotM USB on LPSU vs. Pi2AES AES into Yggdrasil.

    I am not trashing the Pi2AES, I was happy with it and did not have any complaints. But I also encourage people to read @rlow 's comparison, take it seriously and experiment themselves. I read his assessment as an understatement now. The difference in my system was huge.

    This goes for two channel. Don't know about headphones.
     
  16. Garns

    Garns Friend

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    My memory is that Unison is actually powered from the Yggdrasil power supply (unlike Gen5 which is bus powered as you suggest above). However it definitely doesn't work without the +5v pin connected (from experiments with masking tape). But as @purr1n says it might only use the +5v for handshaking so be happy for it to be disconnected after a session is established.
     
  17. JeremiahS

    JeremiahS Almost "Made"

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    Interesting but I have always think that this works more or less the same as USB isolators like Intona and similar units.
     
  18. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    With that many differences it does not seem reasonable to conclude anything other than the entirety of one chain is better than the other entire chain. You could just as easily have concluded that Yggdrasil USB versus Yggdrasil AES is much better.

    Not sure why this bugs me so much!
     
  19. Taverius

    Taverius Smells like sausages

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    I tried that but my only spare PCI-express is right above the GPU which is about the most adverse environment imaginable.

    I'm also using nearly all my sata power cables for watercooling so that powerline is dirty as hell which doesn't help.
     
  20. bobfa

    bobfa Acquaintance

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    I have tried MANY different approaches. Including the several audiophile USB cards. The best I was able to do was using the ADNACO fiberoptic USB extender system. Of course all of this requires a "B.A.PC" running all the time. I still want to test some more but I never found nirvana and a bigger electric bill... Two Pi's and Two Supplies.....
    https://www.adnaco.com/products/s3a/
     

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