Raspberry Pi I2S to SPDIF Hat

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by Michael Kelly, Apr 30, 2016.

  1. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    Did you use the standoffs that we supplied?. They set the space at 18 mm, which is a little bit more than the header would by itself. And you have discovered why we do that!

    Cheers,
    Michael
     
  2. JuleZ3C

    JuleZ3C New

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    Hi Michael,

    Have to say that I had to cut the BNC connector pins also while using your stands... guess you could add one mm and still be more than okay header wise
     
  3. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    Thanks for the feedback. It looks like we should clip the BNC anyway, just to be safe.

    Cheers,
    Michael
     
  4. auri

    auri Facebook Friend

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    Yup, 18mm standoffs. I figured it was just because my RPi USB port was cattywampus.

    What @Grahad2 said. You can also get the program Stream What You Hear on Windows that does exactly what it says to a UPnP device. There's a couple second delay involved, but I haven't messed with it too much because my RPi has decided it doesn't want to detect i2s soundcards and I'm pretty sure I need a new one. :/
     
  5. Merrick

    Merrick A lidless ear

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    Michael was kind enough to offer replacements to anyone whose 502DAC buzzed, and I got mine in today and can confirm that it is buzz free.

    @Michael Kelly I want to thank you for taking so much time to provide a valuable service to this community. You've turned out a product that is, as far as I can tell from the research I've done, a cut above anything else on the market. I wish you all the success in the world with it and I will be recommending anyone interested in using a Pi for audio to get one of your hats.
     
  6. Merrick

    Merrick A lidless ear

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    I had this same issue, and the same solution worked. This was causing dropouts in 24 bit files, but not 16 bit oddly.
     
  7. noise11

    noise11 New

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    Ok I compared my 502dac with the digi + transformer version. Listenting mostly folk music I noticed improvement in clarity, a bigger soundstage with better instrument separation, thight bass and also better decays too, IMO and for the price the 502dac is a clear winner . my system is : rpi2b w/ ifi ipower 5v >bnc/bnc cable with rca adapter> nuprime ida-8 > canare starquad speaker cable> kef q100 biwired. Great job guys.
     
  8. Jeffjazzer

    Jeffjazzer New

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    I have my 502 up and running with no buzzing. Build quality looks great. I'm running it through a Pi3 and have run PiCorePlayer software and now I'm trying out Moode. I am using the Ifi ipower power supply and am running the dig out with an rca adapter in the 1/4" output and an optical cable comparing any differences. Cut to the chase - it has great detail and soundstage BUT it sounds thin, bright and fatiguing! No warmth. Lower mids are not full of enough. I spent a good part of the day yesterday comparing different setups. I've compared my Pioneer DVD player used as a transport (coax spdif) into my Modi Multibit dac and a computer running Daphile using either USB or optical out from the Asus motherboard. The differences in sound quality between the Daphile setup and the transport are very small. The sound coming from both sounds very natural and full bodied, without being bright and thin. Not fatiguing. The transport sounds the best followed by the Daphile computer optical out then the USB out which sounds a tiny bit dirty, but differences are small. I am surprised at the poor sound quality of the Pi3 + 502 hat. Curious if anyone has similiar comparisons. Somebody please compare the sound of your CD / DVD Dac combo to the Pi3 / 503. Curious what others are hearing. Any technical help appreciated from the inmates here to improve the sound from the Pi setup. I was hoping to be able to get my big computer out of the room and replace it with the Pi.
    System is Eminent Technology 8 speakers, Supratek preamp & Pass Labs amp. Thanks for any help!
     
  9. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    I assume you mean you are using an RCA adapter to the BNC? Have you looked to see if the pins might be shorting as a few other folks have found?

    Also, you might try to remove the RCA/BNC jumper to see if the sound improved. Normally leaving the jumper in provides the highest voltage which is usually the best, but it might be causing some small interface problems with your specific device.

    Please keep us all posted on your results. Thanks!

    Cheers,
    Michael
     
  10. haywood

    haywood Friend

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    It could be lack of synergy with Jeff's equipment or that he's gotten so used to the current sound of his components that anything different sounds "off". I haven't noticed it being especially thin or bright but I like silk domes and warm/dark speakers so might not be the best person to judge.

    Jeff you might want to try running with just the Pi for a day or two without comparing back and forth and then compare to your old gear and see if you still feel the same way.
     
  11. Jeffjazzer

    Jeffjazzer New

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    I did a quick test comparing the analog out of the 502 to the digital out to my Modi Multibit. I didn't notice the brightness with the analog out. I am using an 1/4" phone plug to rca adapter where the 1/4 to XLR adapter would go. I'm wondering if this creates an impedance mismatch.
     
  12. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    That might be the issue. The 1/4" jack is a balanced output designed to go to the XLR adapter only. Not to a single ended RCA connector. Try using the BNC with an RCA adapter

    By the way, to everyone watching this forum, should we include a BNC to RCA adapter as well? Seems like the RCA is more popular than BNC. It wouldn't be very expensive and it would seem like a good item to have without expecting a user to dig one up.

    Cheers,
    Michael
     
  13. haywood

    haywood Friend

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    Maybe let users choose between the two adapters? I imagine most would go with the cheaper BNC to RCA since that's a much more common connector and that should cut your costs a little.
     
  14. Xen

    Xen Friend

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    I would expect most users to have RCA SPDIFs and not BNCs. In would even guess that BNC is the rarest connector for consumer products as AES/EBU and balanced XLRs are probably more abundant than BNC. I have a Schiit Gungnir Multibit which happens to have a BNC input so I am very happy with having a BNC output.

    Unfortunately, I have not had the time to setup my Pi3 and still need to make a suitable power cable to hook up the 502DAC to a bench linear power supply so that it can also power the Pi3.
     
  15. bilboda

    bilboda Florida boomer

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    I dunno, bnc to rca are cheap and readily available on the interweb. This hefty adapter aes to trs is probably rarer. I don't know if I will ever use it but it's nice to have jic.
    Early results.
    Installed my 502dac today, clipped the legs on the board, Set up picoreplayer 3.11 (audio enhanced version) with the Hifiberry dac+ driver, removed the jumper and used bnc to rca. The board is solid. I like it. The digi+ pro looks like a little brother visually. Performance is close. Can't A/B them but I compare them with my Win10,Bughead, Fidlerized pc usb to regen to Aune X1s. I see a dac on the horizon. Modi Multibit, denafrips ares or something else. The digi+pro fared well with an underclock. It matched or exceed the pc. I will see how this board does with an underclock.. iFi power supply feeding the hat and then the pi3. It sounds great, certainly not a step back.
     
  16. mo.fu

    mo.fu New

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    Maybe just offer an adapter in your shop. Safes people from paying shipping twice.
     
  17. haywood

    haywood Friend

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    For people asking about power supplies, more evidence that not all lps are created equal and the iFi seems a very good deal:

    https://www.computeraudiophile.com/forums/topic/31119-power-supply-8-group-test-lps-and-smps/

    For voltage stability and ripple it basically comes out on top, though the comparison is mostly to cheap Chinese lps like you'd find on eBay (and the only one that tested decently was the zerozone which like I said earlier uses a copy of an AMB design).
     
  18. neogeosnk

    neogeosnk Friend

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    Let us know how it goes. Need to get one printed also or come up with a solution. I like the way it looks all naked without a case, but the wife doesn't o_O
     
  19. Grahad2

    Grahad2 Red eyes from too much anime

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    Thankfully @Michael Kelly you guys have it packaged really well, cause the local postman seems to have just tossed it over the fence and onto my garden DURING A RAIN. :mad:

    The outside may be wet but the insides contain moist audio. ;P

    Edit: Even the optical connector is preeetty close to the USB. It's far enough that I didn't clip it, but I did put some electrical tape on the USB headers to make it. Don't have a macro lens or proper lighting so it's not the most illustrative photographs.

    BNC before clipping:
    [​IMG]

    Optical:
    [​IMG]

    Yeah, will try to get one up ASAP, some snowballed screw up from a guy before me is causing long work hours recently.
     
    Last edited: Mar 29, 2017
  20. Jeffjazzer

    Jeffjazzer New

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    Update on my 502. I received the BNC to RCA adapter today from Amazon. Less than $5 gold plated. It came from Monoprice.
    Well who woulda thought that cables & adapters make a difference. Ha! Crazy audiophile talk! Well it is true. I should have known better. I built all of my cables out of good Beldin stuff ala Jon Risch recipe (over at Audio Asylumn if interested).

    That adapter made all the difference in the world. Much better sounding than my cheapie optical cable. No longer thin sounding, Everything is fleshed out the way it should be. High end is a little softer than I am used to compared to from my Daphile setup, but I may have been hearing some hash added up there that made it sound hotter. Don't know, Dare I say I am hearing more detail and a bigger soundstage than any other prior setup.

    I would suggest that Michael give the user the option of the BNC to RCA adapter or XLR adapter. Most are using RCA here I believe.
    I was going to throw in the towel on this little 502. Now it's a keeper. I get very emotional when stuff doesn't sound right. Being a musician and an audiophile, I'm obviously very passionate about this stuff. Think I will try to do Scott Kramer's I2S mod to my Modi Multibit next week and see if I can extract a few more percent out of it. Yes we are crazy audiophiles! Digital has never sounded so good, and on the cheap no less!
     

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