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 7" Display case for the PI2AES is now up in our store. Lead time is 1-2 weeks. This case supports both the PI 2/3 and PI 4 as well as the upcoming AKM DAC. We will have an assembly manual and/or video some time this week. Also .dxf drawings for those who want to cut their own.

    http://www.pi2design.com/store/p23/PI2AES_Acrylic_Case_for_7"_Display.html

    Cheers,
    Michael
     
  2. famish99

    famish99 Friend

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    For the record, Rockna I2S spec does use a backwards LRCLK polarity it seems and requires you to jump in the +5V rail, but I recently updated to the 4.7 FW version which sets the second I2S input to PS Audio spec and it works great now, early impressions seem to show better air and details compared to even the Rednet 3...
     
    Last edited: Apr 27, 2020
  3. msommers

    msommers High on Epipens

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  4. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    It does not come with any case parts. Unfortunately the new rear piece that has the opening is not compatible with the old case. It is included with the new case however. Unfortunately you would have to get a new case, which probably doesn’t make sense if you’re only trying to make the opening for the RJ 45. As most other seem to have done, makes the most sense to simply remove that piece. Sorry.

    Michael
     
  5. msommers

    msommers High on Epipens

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  6. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    It’s on the rear where the micro SD card is. Not sure when I took those pictures, but I guarantee the new case has the opening!

    Cheers,
    Michael
     
  7. msommers

    msommers High on Epipens

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    Roger that. Cheers!
     
  8. Nanekiu

    Nanekiu New

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    What's the max sampling rate for the i2s HDMI output, does it support DSD256+,768khz?
     
  9. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    The raspberry pi (and thus the Pi2AES) supports up to 192 kHz PCM only. So that is the limiting factor for the HDMI connection as well. The raspberry pi does not support DSD over the I2S interface, but it does support DSD over PCM (DoP).
     
  10. Nanekiu

    Nanekiu New

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    Ahh i see i need higher samplerate support though as i use HQplayer which is basically a software version of chords M-scaler.
     
  11. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    Understood, it is certainly a limitation that others have expressed dismay at. And I certainly will not enter the often irrational, non-scientific, border-line religious debate about the sonic value of higher sample rates!
     
  12. Taverius

    Taverius Smells like sausages

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    Still waiting for someone to explain how that stuff bypasses the laws governing entropy and the conservation of information, it could revolutionise the field of physics.
    :drunk:
     
  13. gridmaster

    gridmaster Facebook Friend

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    I got my Pi2AES setup today.

    A few special notes:
    #1 I took the 5v jumper off, and am powering the Pi itself with iFi iPower X.
    #2 I was told by a few that the Pi4b has a noisy PCB compared to the Pi3b. Thus I have this setup with a Pi3b.
    #3 I'm running Ropieee OS + Roon.
    #4 It is connected via Ethernet. I initially tried it with built in Pi WiFi, was significantly worse.

    I've tried too many transports to list, but my current ones are Lynx AES16e, and Singxer SU-6.
    Taking those as a comparison point.

    My general chains I've tried this on:
    #1 EAR Dacute 192 (modded) -> EC Jr. 300b -> HD800sdr
    #2 AGD Singularity 7 (factory upgraded) -> Pentode amp (class A, nfb) -> Omega Alnico Monitor

    For chain #1 I had to use spdif from the Pi2aes. For Chain #2 I used i2s from the Pi2aes.

    I'm going to keep this short. The Pi2aes is the best transport I've listened to. I consider the Lynx-Aes16e and Singxer SU-6 on the same level, trading blows with each other in certain expects. The Pi2aes to me is clearly better than both in all aspects of SQ. More nuance, low level resolution, air, micro dynamics, with zero digital hash or glare.

    Thanks Michael for such a splendid product!

    [​IMG]
     
  14. famish99

    famish99 Friend

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    I heard this as well and ended up trying swapping out my original pi4b for the pi3b, since I wanted another pi for embedded experiments anyways. The gain was marginal with the pi2aes, but still appreciated, gave it a touch more air and fluidity.
     
    Last edited: Jun 5, 2020
  15. Biodegraded

    Biodegraded Friend

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    Pi2AES has arrived and replaced HifiBerry Digi +. Impressions per UPnP over wifi (to Volumio on the Pi) -> transport -> Modi Multibit v2 -> MCTH -> HD6XX.

    First impression was 'whoa, this thing does transients'. Attacks are sharper, decays cleaner. Imaging and resolution are also improved. I'd been using optical from the HifiBerry, now it's coax from the Pi2AES via the video ports of a 2-in-1-out AV switch box which also takes coax from my CD player (Marantz CD63 Mk II), so optical vs coax could at least partly account for the differences.

    Comparing FLACs ripped from the same CDs between the Pi2AES and the Marantz, the difference is much more subtle, possibly at expectation-bias level. Attacks are maybe a little sharper from the Pi2AES; cymbals are perhaps a touch more 'hashy' from the Marantz. This contrasts with what @rlow heard from his Arcam CD73 vs the Pi2AES (noticeably sharper transients from CD).

    Power, for full disclosure, is a 5v 1A linear wall-wart (old Iomega Zip-Drive supply) to the Pi (model 3B) and @Clemmaster 's favourite Jameco 24v 0.5A linear wall-wart to the Pi2AES.

    I haven't listened from speakers yet, which might change things, but as it stands now my favourite digital source is a toss-up. The convenience of streaming, though, is hard to beat.
     
  16. rlow

    rlow A happy woofer

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    One thing I’ll mention - when I tried powering the Pi and the Pi2AES separately, with the Pi being powered by an Apple 5V switcher, and the Pi2AES board from my Sbooster, the sound quality diminished a lot. Just powering the entire unit from the Pi2AES with Sbooster was way better, and if I recall correctly, same with powering from the Meanwell stock supply for the whole unit (via the Pi2AES) - it was better than running the seperate Apple supply on the Pi board. So I’m not sure if the separate Iomega supply is helping things here or not for you. YMMV and all that.

    Edit: being that the Jameco is only .5A, you probably can’t use that for the entire unit. But if you can find another 18-24V switcher around, you may want to try that on the Pi2AES and put the pin back in to power the whole unit - using a linear supply vs a switcher didn’t make as much of a difference for me in that configuration as the cheap supply on the Pi (which as I said was much worse).
     
    Last edited: Jun 12, 2020
  17. Clemmaster

    Clemmaster Friend

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    I would agree with @rlow.

    The Pi2AES is not electrically isolated from the Pi. Using 2 power supplies could be suboptimal.

    When I'm not feeding the whole thing with a Jameco, I feed the whole thing 5V directly (UpTone LPS-1), bypassing the on-board DC-DC converter. In both cases, it's one PSU for the HAT and the Pi.
     
  18. Biodegraded

    Biodegraded Friend

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    Interesting, I'll try that. I have a 24V and a 28V that should each have enough current (1.25A) for both boards. I suspect I've passed the limits of resolution of my system (not to mention my ears) by now though...

    Edit: But not immediately, because both have 2.1mm plugs so I'll need to cook up an adapter. I should mention too that both are switchers.
     
    Last edited: Jun 12, 2020
  19. gridmaster

    gridmaster Facebook Friend

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    How are you powering the pi + pi2aes shield with just a 0.5a Jameco? That's enough power for both?

    The stock pi3b wall plug is 2A by itself, so that surprises me.
     
  20. Clemmaster

    Clemmaster Friend

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    It's 24V @ 0.5 amp => 12W
     

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