Raspberry Pi I2S to SPDIF Hat

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

  1. HumanFly

    HumanFly Acquaintance

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    Could you make it a square? Because looking at it you can only make it like 1mm bigger before you come too close to the usb cutout below. (I also tried an optical cable that didnt fit the hole on the 502 housing. Not by much so maybe 1mm is enough). If it`s square you might get some extra wiggleroom. Just thinking along here. I don`t use the optical anyway.
    edit:
    And yeah I know that a square doesn`t take a larger plug than the circle...but you could extent it upward/sideways a little further.
     
    Last edited: Mar 31, 2019
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  2. HumanFly

    HumanFly Acquaintance

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    sorry-couldn`t delete the added noise
     
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  3. bigbear1997

    bigbear1997 Acquaintance

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  4. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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  5. HumanFly

    HumanFly Acquaintance

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    Those are big, but I tried this one(if I`m not mistaken) and it didn`t fit through the (standard) hole in the casing.[​IMG]
    I`ll try and get a diameter of this one for you tomorrow.
     
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  6. msommers

    msommers High on Epipens

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  7. haywood

    haywood Almost "Made"

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    Looking at the prototype board with the stacked combo connector housing it seems like it’d be better to just have a cutout for that whole rectangle rather than trying to accommodate individual holes for the two connectors.
     
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  8. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    That is a very good idea. In the past I didn't want gaps around the connector, but the combo connector has a fairly sized body so I think your suggestion is spot on. Note that this would be for the bottom half. I still need the screw hold to allow the case to lock in for rigidity.

    Cheers,
    Michael
     
  9. bigbear1997

    bigbear1997 Acquaintance

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    Not sure why it is so big but all audioquest toslink cables have similar size head. Dont really know why 8)

    Ps. I have the original 502DAC so probably wont buy the new one but it may be helpful for others with audioquest cable.
     
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  10. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    Folks,

    Does anyone have an I2S over hdmi DAC they can lend me for testing? Gustard or PS audio pinout. I will return the unit within a few days and send a PI2AES production unit as a thank you.

    Cheers,
    Michael
     
  11. lehmanhill

    lehmanhill Acquaintance

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    Sorry. My i2s is not HDMI.

    Another optical cable head diameter data point for you. I have a Hosa (common and inexpensive) optical cable that I had never tried in the 502 DAC case. It didn't fit and the diameter of the cable end at the case is 13 mm.
     
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  12. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    Mm

    Thanks. That is actually not much smaller than the audio quest which I think is 14.

    Cheers,
    Michael
     
  13. HumanFly

    HumanFly Acquaintance

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    Mine (the Argon) is about 13mm. Might be 14 too. (Sorry I could not find my precision tool)
     
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  14. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    I didn’t actually measure it myself. I simply knew the size of the optical end and blew up the drawing and estimated it based on that! Not perfect but sizing it up to 14 mm should ensure everyone can fit their favorite cable.

    I will even look at changing the 502DAC case in the next revision to accommodate that size if possible.

    Cheers,
    Michael
     
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  15. hifiandrun

    hifiandrun Almost "Made"

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    Hi Michael. I sent a PM earlier. Please check if you haven’t read it. Best.
     
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  16. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    I wish to thank member hifiandrun for his generosity in lending me his Gustard DAC X-26. I was able to test the I2S over HDMI and will be posting a full write up of the results in the next few days. Quick summary is that with a very high quality DAC like the Gustard, there was only a small, but measurable improvement in jitter performance, but nothing measurable in THD +N output. With lesser capable DAC's it could make a big difference versus SPDIF, but only if said DAC has I2S input.

    Still it does indicate that the PI2AES is a great core component in a DIY setup using other board level DAC's such as Buffalo DAC's and others.

    Cheers,
    Michael

    P.S. hifiandrun is also lending me his Allo Digione Signature so we can test directly against it. I will also post those results as soon as possible.
     
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  17. hifiandrun

    hifiandrun Almost "Made"

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    Thanks for Michael's kind word. The new Pi2AES is exciting. I did nothing but to help myself to get better transports. I figure that using a stand-alone streamer serves me better than a long (and can get costly) USB chain between my laptop to a DAC. I have been enjoy using two Michael's 502DACs, one for SPDIF BNC to my Gungnir MB speaker setup and another in my HP setup for years. I stream music from both local SSD and from Tidal Hi-res using piCorePlayer. Here is my previous report on 502DAC:
    Raspberry Pi I2S to SPDIF Hat

    I ordered an Allo Digione Signature and it is on its way to me. Read too many good things about it thus I wanted to try it myself. I will do my listening evaluation with the 502DAC first, then I will send the Allo board to Michael for measurement. And I will compare the Allo with the new Pi2AES once it is available, exciting.

    Now this is my disclosure about the Gustard X-26. The X-26 is a loaner from the Chinese vendor Shenzhen Audio. Several years ago I purchased several USB/SPDIF converters from Shenzhen Audio and had good customer service experiences with them. We kept in touch once in a while. When I mentioned that I had a feeling that those DACs using 9038 chips would be promising, I was offered to have a X-26 for a listening, but I don't own the unit. @Vtory recently did a detailed review of this DAC before my loaner unit arrived. I don't think I can do better than Vtory ( https://www.superbestaudiofriends.o...ard-dac-x26-impressions-and-discussions.7654/ ). But I am curious to compare the Gustard X-26 with my Gungnir MB, a new D/S DAC versus MB DAC so to speak.
     
    Last edited: Apr 9, 2019
  18. Roman James DIO

    Roman James DIO Rando

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    Hi michael, I have an idea to power 502dac directly from a 3.3v battery lifepo4 bypassing the standard stabilizer on the board.
    How is this best done?
    the board has a pin marked 3.3v, can I apply battery power here without removing the standard stabilizer from the board?
    thank!
     
  19. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    You would not be able to power from external 3.3V without removing the 5V to 3.3V LDO. Sorry.

    Michael
     
  20. Roman James DIO

    Roman James DIO Rando

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    If you remove the standard stabilizer 5v to 3.3v, it is enough to supply power from 3.3v battery to one point.
    or somewhere else?
    What is there on the board with spdif buffer in this sense?
    Thanks.
     

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