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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    The reviews so far seem to indicate an external low noise supply has some benefit, but even with the standard pi USB power it seems to work very well. Maybe some of the reviewer's can chime in here?

    Cheers,
    Michael

    PS when I tested the recovered clock accuracy with the dScope I was using the USB power supply. I have a low noise bench supply that I also tested with, no difference. But that supply is not the lowest you could get.
     
  2. Kattefjaes

    Kattefjaes Mostly Harmless

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    Oh, that'd be interesting, thanks. Email sent.

    Lack of analogue is no bother here- I was toying with the idea of a second MPD box as an alternate source for my desktop headamps, via a Modi Multibit. It'd be nice to see if there are any easy wins for reduced acoustic and electrical noise, with the large PC switched off, for decadent late night listening.
     
  3. Merrick

    Merrick A lidless ear

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    I emailed you about one of those, I'm happy to pay. Thanks!
     
  4. haywood

    haywood Friend

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    I think I'm one of the ten but covering your postage seems like the least we can do. Feel free to add me to the pay column.
     
  5. auri

    auri Facebook Friend

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    Thank you for the opportunity!

    Been checking in here sporadically waiting for news, thinking about stuffing one of these in a chassis of some kind with an AMB sigma11 PSU. Might be overkill in terms of current but the noise performance (<10uV) is pretty good. Wonder if Schiit will sell me an empty Bifrost box...
     
  6. Scott Kramer

    Scott Kramer Friend

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    Can you measure phase noise also?
     
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  7. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    I am not sure. I'll need to look into it. The dScope manual does not mention it as a measurable item.

    Cheers,
    Michael
     
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  8. hifiandrun

    hifiandrun Almost "Made"

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    My experience is that I haven't gotten any PS worked smoothly with an external portable HDD attached to on-board USB. Some portable HDDs will work if you don't have other stuffs connected such as wifi dongles, usb keyboard transmitter, etc. If your external HDD is a SSD maybe ok since SSD use less power. A separated power supply is not required for 502DAC to be functional. But a nice linear regulated power supply for the 502DAC board will bring the sound quality to another level, IMHO. the 502DAC board consume less than 100mA.
     
  9. darkstar>eyesoftheworld

    darkstar>eyesoftheworld Rando

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    I have a 2TB and 1TB non SSD. I've heard a 20 dollar powered USB hub will do the trick.
     
  10. pandather

    pandather Acquaintance

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    There's a setting to increase max usb output current here: https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=100244.

    I've had this setting enabled on my pi for about a year no and I've had 0 issues while using a solid power supply.
     
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  11. hifiandrun

    hifiandrun Almost "Made"

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    I always set up my Pi this way, but still limited to a total 1.2 amp for all four USBs. In my case, if I have other dongles in the USBs, the HDD will not boot. You are right about the solid power supply. Not all PS rated 2.1amp can withstand the peak needed to start a HDD (about >=1 amp). Sorry I am a little bit off the 502DAC related topics. Will be back on track. cheers
     
    Last edited: Feb 2, 2017
  12. Kattefjaes

    Kattefjaes Mostly Harmless

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    Rather than jury-rigging a hard drive on your Pi, it might be better to invest in a small NAS to live on your network. You can get surprisingly good little boxes for reasonable amounts, these days...
     
  13. minio

    minio Rando

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    Hello,

    Testing unit finally arrived home previous days. Unfortunately I will be busy this weekend so I cannot do extensive tests as I was planning.
    IIRC, @Michael Kelly says to don't test analog part of the board because something was messed up when changing RCA to gold-plated ones.
    Although that, I had some spare time to test it, even if I knew something can go wrong.

    mOode audio v3.1 on Pi 3, AAK on, Resampling off, DAC+ Pro overlay selected.
    Home Rig: Technics Vintage Pro-Series [SU-9070 (preamp), SE-9060 (amp), SH-9020 (vu-meter unit), SH-9010 (eq)] + Wharfedale Xarus 5000 speakers.

    I started listening one of my favourite song (Michael Ruff - Wishing Well) and immediatly heard something weird: starting guitar was coming from centre of stage and not from far left of it. I stopped listening and double-checked settings and connections: they was fine. Then I tried an L/R test voices and they was still coming from the centre; Lastly, i can't hear any out-of-phase sound. I came to conclusion that card was like playing in mono channel.
    Another strange thing is, when music is stopped for about 3 secs, I can hear some fuzz-noise coming from speakers, but when listening to music, it totally disappears.

    Even if I cannot judge instrument separation and width of soundstage, I was literally disarmed about the 'taste' of the sound and great amount of details that came up from speakers.
    Sadly I can't take advantage of full quality of card but that was expected till start, like I said.

    That was a fast review due to analog faulty part, extensive test will come in next days using digital toslink in HAT's final placement: my car.
     
  14. Vastx

    Vastx Facebook Friend

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    Hi everybody, I've been far from this thread for a while... It's nice to see that things are moving forward somehow.
    @Michael Kelly Don't get discouraged, I know eventually we'll get this hat right and it will be a nice sounding board, judging by the prototype I have at home.
    By the way, I'm a little disappointed I didn't receive one to test! :(
     
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  15. Kattefjaes

    Kattefjaes Mostly Harmless

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    It sounds like only the analogue bits are really having trouble- clean, stable digital outs may well be a more powerful feature, long and medium term. Get that right, and the sky's the limit with SQ.
     
  16. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    The one you got before has the same digital as this current one. It was merging in the analog function in that I messed up.

    Cheers,
    Michael
     
  17. Vastx

    Vastx Facebook Friend

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    Good to know. Cause in the meanwhile the digital section kicked ass and those who listen to this transport can't believe it is this good and cheap :)
    So the double clock can work with the same software of the digidac pro?
    I'd like to drop the modified volumio you provided for moode audio.
     
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  18. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    The 502DAC uses the PCM5122 to select the clocks. This allows it to behave as a Hifiberry DAC+ Pro with the digital output being a copy of the analog. The Digi Pro uses Raspberry Pi GPIO to select the clocks. When you get the final revision (which is going to all testers when it is ready) you will need to change the selected DAC to the DAC+ Pro.

    Cheers,
    Michael
     
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  19. Vastx

    Vastx Facebook Friend

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    So the speed 2 prototype I have, which has no dac, can operate properly (with dual clock) with any other OS like moode audio?
     
  20. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    Yes, but I don't know if the GPIO mapping matches the Hifiberry Digi Pro. On the SPD2 we used Raspberry Pi GPIO as follows:

    GPIO5 - 1 = select 27Mhz Clock (default makes it the same as a DIGI+, not Pro)
    GPIO6 - 1 = select 22.579Mhz (used for 44.1Khz and it's multiples)
    GPIO7 - 1 = select 24.576Mhz (used for 48Khz and it's multiples)

    Cheers,
    Michael
     

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