Garns' bang-for-the-buck digital source

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by Garns, May 19, 2017.

  1. Garns

    Garns Friend

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    This is a report on a project I have been fiddling about with for ages. The goal is to produce for minimal $$$ a self-contained, small form factor, passive PC which can support a Lynx AES16 and serve as a digital source/network streamer/etc.

    All in, the cost is about $500-600US. $450US (looks like I can't add up!) I finished this last week after working on it sporadically for about six months. The sound quality is superlative. I started this project because I didn't like the fans in my tower when I was listening to music. Not only is this new setup completely fanless, but it sounds better than running the same Lynx AES16 card in my tower PC. Actually, significantly better.

    This isn't really a how-to guide, more a documentation of what I did in order to alert other people to possibilities and to indicate what worked well for me.

    THE BASIC SETUP
    The goal is to use a mini-ITX motherboard with a PCI (not PCIe) slot, to take advantage of the super cheap pro PCI cards out there. Box the whole thing up and you are ready to go. Everything here should be findable on eBay for peanuts. I should warn that this project is based on technology which is about 7 years old, so there is a reasonable chance that any of your components could go tits up at any moment.

    SOUND CARD
    Lynx AES16. I got one off Ebay for $175 US. You need a breakout cable. The one that comes with the card is very bulky. Probably better to get a card without cable (cheaper) and get Redco to make you one up for $25 (link). If you need S/PDIF, you can get the RME9632 instead. AES from the Lynx is marginally better than AES from the RME.

    THE COMPUTER
    After a bit of research, it seems that the best motherboard to use is the Intel D945GSEJT. Low-power, has the requisite PCI slot but also can be powered entirely from a 12V DC input. This simplifies the whole power supply side of things (more on which later). Otherwise has the usual complement of connectors. You also need:
    • RAM. You want a single 2gb DDR2-553 SODIMM. DDR2-667, -800 or -1066 is also fine.
    • A SATA SSD hard disk. You also need an SATA cable and an SATA power cable. You could get a high capacity drive and load all your music on it, or a small one and store your music externally (external HDD or NAS). The second is what I did, so I have a 32gb SSD in there.
    • (Optionally) a wireless card. This needs to be a Mini-PCIe card, and you will need to buy a U.FL IPX to RP-SMA pigtail to connect the card to an aerial on your case, and also an aerial.
    THE CASE
    Here is where it gets more interesting. There are many choices out there. I ended up buying a Minibox M350. This is a really tiny case for a Mini-ITX motherboard, available in the US for around $40. The D945GSEJT drops in with no problems, but in order to use the PCI slot you need to buy a special PCI riser kit specific to the case and the motherboard. This is quite hard to source, and I was helped out Han Soloing it out of Sweden by @KurtSvensson, but subsequently, I found that you can get it easily from a UK site (on this page at the bottom). If you email them, they can ship it to you at reasonable cost.

    If you go this route, it is essential that you get an SATA cable and SATA power cable with a right-angled connector at one end. The clearance inside the case is very tight, and you won't be able to fit the AES16 over the SATA connector on the motherboard if you use a straight connector.

    Another option is the slightly taller Minibox M300, which takes a readily available PCI riser card to use the expansion slot. There may be a concern with heat dissipation in either case. The M350 is really compact without much room for airflow. The M300 is bigger, but has no ventilation holes. The M350 seems fine at the moment, and doesn't appear to get warm, but it's winter here right now.

    POWER SUPPLY
    The D945GSEJT takes a standard 12V DC input, 5.5mm outer diameter, 2.5mm inner diameter. I went for a 65VA supply, which can put out 3.5A of current. This is pretty conservative and probably overkill. At first I bought a shitty $10US switching power supply off Ebay and it sounded like crap. I subsequently bought a linear power supply from China for about $110US. Big improvement. But get a cheapie SMPS at first while you get everything running. You could already be happy with that.

    Note that the motherboard still has a switching regulator on it to convert the 12VDC input to all the various voltages needed inside the PC, so don't go mad with expensive esoteric linear power supplies. There will still be a residual amount of noise from the internal switcher. So getting reasonably clean power in should be adequate.

    EDIT: @Yeskey also suggests the SOLAHD SLS‑12‑034T (as per this thread), which would be an excellent option and way cheaper if you are in the States (outside the US you will get nailed on shipping).

    SETUP
    You need to run Windows. The Lynx card is not going to work with anything else. I use 32 bit Windows 7. For software I use Foobar 2000. Other choices are possible. If you want to do network streaming etc then Foobar has a uPnP plugin which works perfectly. You could run it headless in this mode by setting Foobar to start automatically at boot-up and then controlling it via uPnP. BubbleuPnP for Android is the one to get. I don't have this set up at the moment since I am happy just using it as a standalone unit plugged into a monitor and keyboard. If anyone wants a sound quality comparison, let me know and I'll give it a go.

    OK, HOW DOES IT SOUND?
    Great. As I said, better than the Lynx AES16 placed in my auncient tower PC (with power supply of questionable origin). This is feeding Yggdrasil -> Freya -> K+H O300D monitors. Lots of nasty sibiliance in the treble is gone. Bass is better defined. Better separation, wider soundstage. Just a lot more listenable. In terms of how significant the difference is, let me rank all the digital sources I tried:

    USB <<<<<< RME9632 S/PDIF in old PC << RME9632 AES in old PC < Lynx AES16 in old PC <<< Lynx AES16 in this PC

    Some gotchas I found. These are all probably very system specific.
    • The PC is on a separate power circuit to my audio equipment (which is run through a Furman power conditioner). The AES cable connecting them has its shield disconnected. Putting the PC and the audio equipment on the same circuit sounded bad. Leaving the AES shield connected sounded bad. Feel free to flame me for audio nervosa but this is quite clear to my ears. The first time I put everything together I got this wrong and abandoned the whole project in disgust as it sounded worse than my tower PC.
    • Plugging in an external USB hard disk made things sound worse. It seems to be purely a power draw thing. Plugging in a powered external USB hub and plugging an external HDD into that sounded no different from using the internal SSD. That's what I'm doing now.
    • Playing around with the buffer sizes for the Lynx, I found 256 was the sweet spot. Any lower caused some sibilance and harshness in the treble. I am pretty certain this is real (but again, probably peculiar to my system). Higher than 256 might have sounded a bit flatter, but I am probably imagining this. In any case, it is free to muck about with this.
    SHOPPING LIST
    Here is what I bought. Everything here is from eBay unless indicated otherwise. There are some links in the text above for specific items. I have converted prices I paid to US dollars from AUD.

    Hardware
    Mini ITX Intel D945GSEJT Motherboard - $22
    2GB PC2-4200 DDR2-533 SODIMM - $10
    32GB SATA-2 Solid State Drive - $22
    Intel 802.11 A/B/G Mini-PCIe Wireless/WiFi Card - $7.50
    U.FL IPX to RP-SMA female pigtail cable - $1.50
    You also need a wifi aerial. I just took one off an old router.
    Lynx AES16 - $175
    Breakout cable from www.redco.com - $25

    Case
    Minibox M350 from www.mini-box.com - $40
    PCI Riser Card and I/O Shield for M350 (Intel D945GSEJT *only*) from www.mini-itx.com - $25

    Power supply
    S22 KG Edition 65VA HIFI Linear Power supply DC 5V/9V/12V/15V/18V/19V/24V 65W - $115
    Or follow @Yeskey's suggestion of the SOLAHD SLS‑12‑034T
     
    Last edited: May 20, 2017
  2. Yeskey

    Yeskey Friend

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    Forgive me as I'm not electrically inclined, but would the sola Hd 12VDC 3.4 amp PSU fit as a power supply as well? Same psu used in the TCC-tc750 mod. What's the average power draw on this micro-computer?
     
    Last edited: May 19, 2017
  3. gixxerwimp

    gixxerwimp Professional tricycle rider

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    I've read lots about the importance of a good source, but not experienced the differences myself. With the variations you tried, it was all AES out from the Lynx. Any idea what the gotcha factors could have been doing to pollute your music with sibillance and bad treble/bass? I'm still of the naive "digital is digital" mindset. Is it not bit-perfect to the Lynx and out to the DAC? Is noise tagging along with the music to the DAC and affecting it there? Sorry for these rather simple-minded questions. I guess this has all been hashed out in the USB Nervosa Thread but I kinda gave up following it.
     
  4. Abhishek Chowdhary

    Abhishek Chowdhary Friend

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    PSU plays quite a significant role in extracting optimum performance from digital sources. Cheap PSU usually have digital haze, veil here and there. With better PSU the veil/haze is resolved to definition. Its not huge difference and it wont fix inherent weaknesses of your audio components but if you are happy with your setup it may be one of the things you may want to consider.
    Similar is the story with board quality, cables, connectors etc.
    Invest in these only if the upstream gear is capable enough.
     
  5. Garns

    Garns Friend

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    Assuming that 3.4A is the actual output current, that is the same output as the 65VA power supply I have got (the 65VA is the transformer before efficiency and regulation losses). So you should be fine. The motherboard manual is here:
    https://downloadmirror.intel.com/17597/eng/D945GSEJT_TechProdSpec.pdf
    and on p55-56 there is a table with estimated power draws for various configurations.

    I think pretty much this. As @Torq explained the Schiit DACs from Gungnir Multibit upwards should be fairly immune to jitter. So it is pretty much noise on the digital input affecting the DAC, I think. For example, with the external HDD, more power draw could cause more power supply ripple. For the power circuit business, I forgot to mention that my audio equipment is on a power conditioner, so putting the PC on a separate circuit insulates the audio equipment from noise from the PC. As for the buffer size, dunno really. The mechanism for some of this stuff is a bit mysterious to me.

    I imagine that from what others have said you can get better performance still with an AES16e in a Thunderbolt chassis or a RedNet setup due to even better isolation from electrical noise but then you are looking at a fair bit more than $450.
     
    Last edited: May 20, 2017
  6. Kattefjaes

    Kattefjaes Mostly Harmless

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    You pretty much nailed it for yourself. Proper AES/EBU, as opposed to just AES3*, mandates transformer isolation at each end of the connection. This keeps stray electrical noise down the line at bay. That noise is not part of the digital signal, it's just electrical hash, as you speculate above.

    Transformer isolation blocks DC effortlessly- bye bye ground loops too.


    * AES3 may be transformer isolated if the manufacturer cares enough, but AES/EBU must be.
     
    Last edited: May 20, 2017
  7. wormcycle

    wormcycle Friend

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    I found a PC raiser card http://www.mini-box.com/s.nl/it.A/id.289/.f that is supposed to fit to M350. Is that the same as the one you used?
    I suppose it mans that the Lynx card is mounted parallel to the motherboard? I almost gave up on installing full size PCI Lynx or Essence into the small Siverstone case and I wonder if that piece would solve my problem.
     
  8. Garns

    Garns Friend

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    It looks like that one fits the M300. It's definitely not the one for the M350, which is much shorter and includes a custom backplate.

    The card does indeed lie parallel with the motherboard. I can't comment on the Silverstone case, but in general you want the riser card from your case manufacturer because the correct height for the riser will depend entirely on where the external slot is on the case.
     
  9. ak2angel

    ak2angel Acquaintance

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    For people who have budget constraint, I would recommend using the Lynx One card instead of AES16. It's significantly cheaper (around $3-40 in ebay) and uses a standard DB25 connector, which is much easier to work with than the high density HD26 connector. The downside is that its driver works only with Windows XP 32bit and max supported sampling rate is 48kHz.
    Soundwise, I found the difference is small when both using AES output, with the 16s had an slight edge in overall coherence and resolution. But hey, the 16s are several times more expensive after all.
     
  10. Xecuter

    Xecuter Brush and floss your amp twice a day

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    Hmm, I want to build one of these and use my Lynx Aes16e. I know you were doing it to take advantage of the super cheap pro PCI cards. But a lot of folks on here already have pro PCIe cards. I guess there is not Intel Board with BGA socket and PCIe?
    Was there a reason to go for a BGA socket?

    Would there be a draw back in using: http://ark.intel.com/products/34688/Intel-Desktop-Board-DQ45EK This has a single PCIe
    Also this will allow you to go for 4gm of ram (probably not a limiting factor in the original build)
    However, you will need LGA775 CPU - cheap as chips online.
    Thanks for doing this Garns!!
     
  11. Grahad2

    Grahad2 Red eyes from too much anime

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    I think the main motivation was a low power, low noise (fanless board), low fuss (no need to source a LP heatsink), and cheap board. PCI cards are cheaper, and the board comes with the CPU included.

    BGA Atom passive boards with PCIe are abundant, and available from multiple brands like Asus Asrock etc.

    Some do say that PCI versions sound better than PCIe, especially if the companies just use a bridge chip instead of a native PCIe solution.
     
  12. ak2angel

    ak2angel Acquaintance

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    BGAs tend to be low power (less psu demanding), and low heat (not require fan/big heatsink) at the cost of performance, which we dont really need much in this particular application.
    If you want to use normal LGA boards, take a look at Gigabyte H170TN, it supports the lastest sk1151 cpus, and could take up to 16gb ram.
     
  13. Garns

    Garns Friend

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    Yep, just this. CPU is already there, no fan, easy DC power connection, cheap, reasonably plentiful.

    The tiny M350 case I am using also has a PCIe riser kit for the Intel DN2800MT which looking at it seems to fit these criteria in the PCIe world. It's not very current though (2012). Dunno about more modern options. Is Intel NUC fanless? That would do the job nicely if so.

    Nb @Xecuter, another local AUS option I considered for the linear power supply is Gieseler Audio. Bit pricier but looks good. There are some threads on SNA.
     
  14. Xecuter

    Xecuter Brush and floss your amp twice a day

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    OK, I understand better now. I have been reading a lot about this topic for the last few months.
    I agree passive cooling and minimal GOOD power is definitely the most important factors in such a build.
    However I want to run a slightly more powerful CPU as it does all the playback and the processing. Power draw difference wouldn't even require a change to the build..
     
  15. mrflibble

    mrflibble Friend

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    I built a very quiet PC a number of years ago because I hate the noise that fans and HDDs make. It is a Core 2 Duo E8400 system (pretty ancient by today's standards). The chassis has two fans running at low rpm, CPU is passively cooled with tower heatsink, Asus motherboard, passively cooled nVidia based graphics, SSD, internal HDD in noise reduction box. PSU is a fanless Seasonic. Sounds almost silent, my Gungnir Multibit makes more noise!

    The original build had an Antec PSU and I experienced significant electrical noise into an external DAC via USB (Audiolab MDAC at the time) when performing anything on screen. I fixed the problem by using a galvanic isolator USB widget. Later, the PSU went kaputt and I replaced it with the Seasonic unit. The electrical noise was gone and the galvanic isolator was no longer required.

    It just goes to prove how important a quality power supply is. It would be interesting to know how my setup compares to a dedicated low power machine similar to what @Garns has built. A rhetorical question, I wonder if there would be any improvement in sound quality using a linear power supply in place of the Seasonic SMPS?
     

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