Raspberry Pi I2S to SPDIF Hat

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

  1. Baten

    Baten Friend

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    Really sweet combos :eek: congrats
     
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  2. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    All good thanks!

    Michael
     
  3. earnmyturns

    earnmyturns Smartest friend

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    Blogged a summary of my Pi2AES setup.
     
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  4. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    May I link to this on our web site? :)

    Michael
     
  5. earnmyturns

    earnmyturns Smartest friend

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    Sure!
     
  6. rlow

    rlow A happy woofer

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    Finally got around to building my Pi2AES unit yesterday but only listened to it for a very short time. However, I have been listening to it much more today while I’m working and I’m enjoying it very much! Bravo @Michael Kelly!

    Will provide some more detailed impressions and comparisons later on.

    In the meantime, a couple of quick things:

    1. I’ve been powering it with my Sbooster power supply set at 10V (which is the highest setting) and it seems to be working great with no issues. Any harm or issues doing that?

    2. You may want to consider including some feet with the case. Without them, the screws on the bottom of the case end up against the surface of whatever it’s sitting on, potentially scratching it (not to mention sliding around). I ended up using some small rubber bumpers that I bought for something else, which works great. Something like these:

    https://www.amazon.com/Scotch-Bumpers-Pack-Clear-SP951-NA/dp/B01N74P0QB

    This is similar to what’s stuck on the bottom of the Micro/Ultrarendu and I believe also similar to what came with an old IFi DAC I bought some time ago. You could just cut 4 out of a pack and throw them in with each case (and charge an extra $1 or something if you needed to).
     
    Last edited: Nov 4, 2019
  7. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    You are cutting it close at that voltage because there is an enable circuit that wants the voltage to be at least 10 V. So don’t be surprised if with the temperature changes or humidity in the air it might get a bit fussy.

    As for the rubber feet, well duh! We used to include them in the past with other cases that we made and I simply have no explanation for why we stopped doing that. We will start adding them right away. Thank you for the reminder!

    Cheers,
    Michael
     
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  8. epistrophy42

    epistrophy42 Rando

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    I would like to share my experiences about my search for the ultimate digital audio playback:

    Since 3 years I am a very happy and proud owner of a fantastic Vitus Audio SIA-025 amplifier. The Vitus replaced the Mark Levinson 383, and with what a difference! Only now I do hear what my speakers (Verity Audio Parsifals Ovations) are capable of. I play vinyl on a Linn LP-12 and as a digital front-end I had a Linn Akurate DS/1 streamer from 2012. I only stream from my NAS, a Synology 1515+ and only use (hi-res) FLAC files. The Vitus amplifier showed a huge difference in quality between the Linn LP-12 and the Linn Akurate DS/1. So I went looking for a new streamer...

    First I got a Linn Klimax DS/3, with the Katalyst DAC that got very good reviews world wide. In my setup it was very disappointing: I thought the Klimax sounded technical rather than musical. It seemed as if the music was literally bit-by-bit demolished/rebuilt with a very alienating and tiring end result. Was that the result of the upscaling process?

    Then came the dCS Bartok: I liked it much more than the Linn Klimax, but I was missing some color/contrast and dynamics. The Bartok also gave a small amount of coloring to the sound of a piano. Furthermore, dCS does not work with OpenHome-UPnP but with the older Vanilla-UPnP so that the Bartok cannot be operated with my favorite BubbleDS app on my Android devices. At that time, there was no dCS app for Android and using other apps I had no gapless playback so listening to classical music was a no-go.

    Thirdly, I listened to the Vitus RD-101 streamer, the first streamer from Vitus Audio and member of the "Vitus Reference" series. I compared this with the DAC of a Vitus SCD-025, a DAC/CD-player from the more expensive "Vitus Signature" series, driven by an Alluxity streaming bridge. I am very fond of the RD-101 1-box solution, but the SCD-025 played much more colorful, dynamic, more musical and real.

    And so I bought a second-hand SCD-025 Mk2, a top-class CD-player with a built-in DAC that can be connected to a streaming bridge via USB, SPDIF-AES/EBU and SPDIF-Cinch. My CD's have never sound that good: much better than the FLAC files ripped from CD's via the Linn Akurate DS/1. I intentionally chose the use the SPDIF-AES/EBU input (instead of the USB) on my SCD-025, so I searched for a streaming bridge with SPDIF-AES/EBU output. I used a AUDIOPHONICS-Digipi+ AES hat for the Raspberry Pi for breaking-in my Cardas Clear AES/EBU cable. This already sounded remarkably detailed and open, but also a bit restless: but thanks to the qualities of the Vitus SCD-025, I already found the end result better than the dCS Bartok.

    After a 4-week breaking-in period, it was time to upgrade the streaming bridge, and I connected a Lumin U1-mini to my Vitus SCD-025. This was very disappointing: the openness and detailing of the Audiophonics Digipi+ was gone, although there was more calmness but the sound image was gray, dull and flat. Weird: the Lumin U1-mini is 20x more expensive than the Audiophonics/Pi combination.

    And in August I read about the Pi2AES. Would this streaming bridge with SPDIF/AES-EBU output be the best partner for my SCD-025? First I had to look for a good linear power supply of 12V for the Pi2AES. I opted for a Farad Super 3, a very expensive ($800,-) PSU from the Netherlands that is extremely stable 12V source. The Farad Super 3 only feeds the Pi2AES hat: the Raspberry Pi is fed with a standard Pi power supply. The Raspberry Pi runs Moode Audio software (v5.3.1) and I use BubbleDS on Android devices as control software.

    The final result is amazing: the Pi2AES brings calmness to the sound image that was missing in the Audiophonics. But what remains is dynamics and energy (Tom Waits), enormous colorfulness and contrast (Classical music with wind instruments) from the lowest bass to the highest treble, stunning three-dimensionality (King Krule - The Ooz, Andy Stott - Passed me by). Now I have very musical, superbly rich/colorfull, controlled, elegant and non-fatiguing sound.

    Thank you so much for designing the Pi2AES!
     
  9. rlow

    rlow A happy woofer

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    Just did a few tests running the Pi2AES from my Sbooster and then hooked up the RPi from an Apple 5V supply (after pulling the W2 jumper from the board so that the RPi used the Apple supply).

    Using the Apple switcher to supply the RPi had an immediate increase in sibilance and loss of soundstage (width, depth and height), a decrease in blackground (higher noise floor) and just an overall sharper and more “FM radio” sound.

    Putting back the jumper and powering via only the Sbooster immediately increased the soundstage, blackened the background and made everything sound relaxed and more naturally detailed without being sharp.

    I don’t have a separate good quality 5V linear supply for the RPi board right now, but I won’t be going back to a regular 5V switcher/wallwart for the RPi board. The differences were not minor.
     
    Last edited: Nov 11, 2019
  10. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    Have you compared it against using just a 12V or 24V switcher to the AES side?

    Cheers,
    Michael
     
  11. rlow

    rlow A happy woofer

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    Not yet. Will have to dig around for one and try that next at some point soon.
     
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  12. epistrophy42

    epistrophy42 Rando

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    Some photo's of my setup with the Pi2AES, the Farad Super 3 power supply and the Vitus SCD-025 Mk2 CD/DAC.

    [​IMG]

    [​IMG]

    [​IMG]
     
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  13. msommers

    msommers High on Epipens

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    I've got an itch to try an LPS on this thing again. I'm considering two things:

    1) 12V, 4/6A device like these to power the whole unit together:
    https://www.aliexpress.com/item/32922596369.html?spm=2114.12010615.8148356.12.8ffe11a63El8mz
    https://www.aliexpress.com/item/32923347778.html?spm=2114.12010615.8148356.42.2c991a9f76DW3T
    https://www.aliexpress.com/item/32921754868.html?spm=2114.12010615.8148356.48.2c991a9f76DW3T

    2) Dual-output LPS. This is where I forget the specifics or tolerances of the Pi and Hat as separate units.

    The Pi I understand likes 5V (a little more if I recall), but can it take more voltage? Additionally, at 5V, it needs something to provide 3A?

    The AES Hat I think can take 12-48V and doesn't really require much amperage, max 1A.

    Apologies, I just want to ensure I have my ducks in a row and my AES player doesn't blow up :)
     
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  14. Clemmaster

    Clemmaster Friend

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    Provided you don’t drive a USB DAC, 5V 1A has always been enough for my, up to Pi 3B+ running WiFi. Never tried the Pi 4.

    The Pi2AES probably needs less than 100mA.

    Although it might void your warranty (@Michael Kelly can confirm), you could run 5V directly off the header of the Pi2AES, too.
    Same current specs.
     
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  15. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    [At 1QUOTE="msommers, post: 278286, member: 2992"]I've got an itch to try an LPS on this thing again. I'm considering two things:

    1) 12V, 4/6A device like these to power the whole unit together:
    https://www.aliexpress.com/item/32922596369.html?spm=2114.12010615.8148356.12.8ffe11a63El8mz
    https://www.aliexpress.com/item/32923347778.html?spm=2114.12010615.8148356.42.2c991a9f76DW3T
    https://www.aliexpress.com/item/32921754868.html?spm=2114.12010615.8148356.48.2c991a9f76DW3T

    2) Dual-output LPS. This is where I forget the specifics or tolerances of the Pi and Hat as separate units.

    The Pi I understand likes 5V (a little more if I recall), but can it take more voltage? Additionally, at 5V, it needs something to provide 3A?

    The AES Hat I think can take 12-48V and doesn't really require much amperage, max 1A.
    o the pi. Mwas m i I
    Apologies, I just want to ensure I have my ducks in a row and my AES player doesn't blow up :)[/QUOTE]

    At 12V the PI2AES itself draws less than 100ma. If the PI is also being powered then you need about 1.5A at 12V total. At 24V the current is half of the 12V figures.

    Michael
     
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  16. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    You would need to be a little bit higher than the internal 5V supply, otherwise the internal supply will actually provide the power. Powering directly from the I2S header is not recommended because there is no overvoltage protection circuit for the PI2AES.

    Michael
     
  17. lehmanhill

    lehmanhill Almost "Made"

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    Just a suggestion on power supplies for the Pi2AES. You might try every 12 to 48V power supply in your house before shelling out for an expensive linear supply. I actually built a DIY psu that has very low noise. When I did a comparison between the DIY and an old laptop switcher, the two had different sound character, but finally, I preferred the switcher. In the end, it is about which components best match your system or make you the happiest, more than what are the best specs.

    As an aside, considering that the Pi2AES has a DC-DC switching converter at the power input, I was surprised that I could consistently hear a difference between supplies, much less that I preferred the switcher.
     
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  18. msommers

    msommers High on Epipens

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    Sounds like a single LPS simplifies life and offers some protection for the AES hat. The 12V @ 4A version seems like there is plenty of power, and 6A is way overkill and unnecessary.
     
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  19. haywood

    haywood Almost "Made"

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    I’ve run a pi3 with a 5v/1a iPhone charger in a pinch but the newer kernels are much more finicky about low voltage situations and will spam the kernel log like mad which is counterproductive from a “keep things electrically quiet” standpoint. The official power supply is like $10 and fairly well done, or if you already have an unused iPad charger you can try that as they test out as fairly low noise.
     
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  20. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    I’m not sure about the preference regarding the sound, but noise coming in can still come through the switcher. We then use very low noise LDO’ S to knock that down, but it is not 100%.

    Cheers,
     

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