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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    You would need to supply 3.3V to the output pins of the LT3042 which is doing the 5V to 3.3V conversion. Obviously you need to remove the LT3042 and wire the return power to the power pad underneath the LT3042.

    Of course, all of this is purely hypothetical and it you do try this the warranty is totally void! But, I also know that it probably won't stop you from trying!

    Cheers,
    Michael
     
  2. Roman James DIO

    Roman James DIO Rando

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    Thank you Michael. Yes, most likely will not stop :) Our sound is everything.
    With best regards.
     
  3. Lateboomer

    Lateboomer Rando

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    May I ask for me who is still using usb dac, could PI2AES also output digital music via usb to dac?

    Or the usb output has to be taken from the rpi board but not the shield?
     
  4. HumanFly

    HumanFly Acquaintance

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    You would need a different HAT for that. Allo had a usb-bridge, not sure if it`s still available.
    Conscensus seems to be that the USB straight from a pi is pretty bad for audio. Pi2aes adds AES and coax connections so you can use the pi as a transport with those connections. If you were to use the USB out of the pi adding a HAT would be pointless (unless the HAT takes a very nice powersupply and powers the pi. Some gains to be had that way but it seems an expensive route to me). To awnser your question directly: usb still has to be taken from the pi.
    Your DAC only takes USB? No coax?
     
  5. Lateboomer

    Lateboomer Rando

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    I agree with what you said, forget taking usb from rpi because it is just a waste for the shield board then.

    However, I just wonder can't P2IAES allso included usb output, like what usbridge does? Would it compromise the sound quality to have an extra usb output? My dac currently only has an usb input.
     
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  6. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    I will have to look into what the USB bridge device does. We use the I2S interface directly to the raspberry pi CPU chip. That will always get you better results than USB because it does not have any of the USB related issues with clocking or noise, etc.

    I have never tried to bridge I2S to USB though I know there are chips that are designed to input audio and send it out via USB. I just don’t know how useful or how well they perform for high resolution audio. But I will look into it.

    Regards,
    Michael
     
  7. Lateboomer

    Lateboomer Rando

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    I fully agree with what you said, direct taking output from I2S is much better than USB, and I have been waiting for sbc with good aes transport capability for a long time. I think the better way is to forget this usb output, but I hope you will give more extensive guide with pic probably later on how to tap from the I2S output and convert xmos usb dac to accept I2S input. The best is to bring PI2AES to the market as soon as possible. :)
     
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  8. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    There is already a preliminary user manual on our website for the PI2AES. The final version is slightly different in that we have added a BNC output along with the RCA, Opto and balanced AES. This necessitated moving the status LEDs to a different spot on the board.

    Now that we have finished testing the prototypes our next step is to begin the first production unit build. We have ordered sufficient parts to build 25 units and hope to have them ready by the end of this month.

    I will post a message to the forum when they are close to being ready and we are taking pre-orders.

    Cheers,
    Michael
     
  9. Yethal

    Yethal Rando

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    Will the preorders also include cases?
     
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  10. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    Yes, though I have to get off my butt and finish the case design! I bought a lase cutter so I could do this in house for low volume and to tweak the design if need be. But I have spending too much time playing and now I need to get serious about finishing the design. :)

    Cheers,
    Michael
     
  11. Yethal

    Yethal Rando

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    That's great to hear, wouldn't want to buy it without matching case. I'm afraid I can't find the manual could you provide a direct url for it?
    btw, the forum link on your website returns http 500.
     
    Last edited: May 9, 2019
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  12. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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  13. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    A quick update on the PI2AES board. We will be putting 10 units in the store next Tuesday. We have bought sufficient parts to build another 25, but because of the upcoming holiday we will only able to get 10 ready.

    Cheers,
    Michael
     
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  14. Thenewerguy009

    Thenewerguy009 Friend

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    Would you know if the PI1AES board can replace the I2s to SPDIF board on a Allo DigiOne signature?
    Would it be as simple as swapping it out & it fitting on the connectors?
     
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  15. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    Not quite as simple as swapping out the connectors! You would also have to change the driver of whatever audio player you are using to the “hifiberry digi+” board. That’s what our board looks like to the raspberry pi OS. Please note that our final production version of the PI2AES has both RCA and BNC options, along with the balanced XLR and Opto output. Add in the parallel I2S and differential I2S over HDMI and you pretty much have a universal Swiss knife digital audio board!

    Cheers,
    Michael
     
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  16. neogeosnk

    neogeosnk Friend

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    Is there a case going to be available also? Does it output from i2s and AES at the same time (have two dacs). Also what dac selection would it be under for volumio or roon?
     
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  17. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    All outputs are active simultaneously. And yes, there will be a case.

    Selection is "hifiberry digi+" as mentioned in the previous post.

    Cheers,
    Michael
     
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  18. Yethal

    Yethal Rando

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    Will you also be selling a matching power supply? If not, will the 12V version of iFi iPower work with the board?
     
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  19. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    The board is designed to accept 9V to 48V. 12V should be used unless the input rail (which is routed to the I2S expansion header) is being used to power a tube based dac/amp add-on. Currently we have a plan for a grounded cathode hybrid tube add-on for later this summer. It will run off 24V or 48V. We will be offering a 24V switching supply as a balance to allow for most use cases.

    If you go with 12V the PI2AES itself needs less than 6W (0.5A). But you need to take into account the total wattage needed by the PI and any USB peripherals attached. Worst case (PI [email protected] 3A + 4x USB [email protected] each) is 35W! So a 12V supply would need to provide at least 4A to be safe. Of course, we allow the PI to be powered separately, but that is up to the user. Our 24V supply will be at least 2A so we have enough power for worst case.

    Cheers,
    Michael
     
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  20. haywood

    haywood Almost "Made"

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    Is there any advantage to powering the pi and the pi2aes separately? I know you said previously there wasn’t really for the 502dac doing spdif but I thought there actually was some benefit to that, so... ;)
     
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