Raspberry Pi I2S to SPDIF Hat

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

  1. Ntbm3

    Ntbm3 Friend

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    Thank you!

    I need to do some more research...

    Just want to run high quality aes and spdif into two sources. The pi still seems like the best value option.
     
  2. FlySweep

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    << Piggybacking on Ntbm3's request.. and this may be more of a general raspyPi question (my apologies if we're veering a but off topic) >>

    I stream a fair bit of music from soundcloud and mixcloud.. can I do this from a raspyPi (+Pi2AES) while controlling from my phone? Fidelity limitations aside, I'd like to be able to stream from those sites and my local network with one tidy setup. Which distro facilitates this and is compatible w/ Pi2AES?
     
    Last edited: Nov 28, 2019
  3. weaver

    weaver New

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    Just updating to say - got I2S working to the Metrum Onyx fine so a bit more on the voltage/current thing: I am currently running a Pi 3B and PI2AES from just a single plug top LPS rated at 24V 400mA. The Pi only has a USB hard drive and ethernet attached but still a bit surprised the current was sufficient. Conversely I also tried a 13.8V 2A bench supply and a 15V 1000mA plug top neither of which worked even when the Pi was powered separately.
    Two caveats to this: all three are working through plug adapters to get the correct barrel size and although it is the same adapter and I have checked output with a meter it is just possible the adapter is causing an issue on the two lower voltage supplies.
    Secondly, the inputs on all are given as 230V but mains is generally closer to 249V here.
     
  4. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    I am surprised the 15 V did not work. But I am happy that the 24V did and we know for a fact that some of you have used 19V successfully.

    Of course, I am really, really sorry about this whole issue. And as mentioned before, if anybody wants to return the unit for a full refund we will gladly do so. If you have a unit that is having trouble and you do not have a 24V supply available, if you purchase one we will refund you up to $25 for it.

    Michael
     
  5. Clemmaster

    Clemmaster Friend

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  6. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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  7. bilboda

    bilboda Florida boomer

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    You can also use picoreplayer with Logitech Media Server. Roon will mamage it and you don't want to install the LMS on your pc, let Roon do it. I have ropieee now but may go back to picoreplayer and LMS or at least install it on another card to compare them.
     
  8. Biodegraded

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    @Ntbm3 , see also here and here in the 'Building a Raspberry Pi-based streamer' thread.
     
  9. weaver

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    Continuing on power supplies: my assumption is that for a Pi/PI2AES to function the external PSU either provides sufficient voltage/current for the unit to function or it doesn’t, and if it doesn’t then lights don’t come on and nothing boots, if it does then as long as no additional load is added the I2S signal will be output exactly the same irrespective of the rating of the PSU. Is this a valid assumption?
    From that, the only possible differences between power set-ups, 2 PSUs or 1 etc., are the amounts of noise (despite the best efforts of the board’s designer) that may be transferred from the Pi/PI2AES to the external DAC and make its way through to the analogue output. Which is to say that eg. the buffer is there to ensure that the digital signals get to the DAC but it can have no direct effect on eg. playback volume due to the power level the external PSU provides?
    Or, can the PSU also have an effect on things like jitter? Not that I would know what that actually sounds like but I am prepared to believe that the difference between an optical output and a coax one may have something to do with signal conversions in addition to electrical isolation.
    Either way, I am curious to know how different forms of noise translate into different perceived results for the listener. One of the more obvious ones is that the presence of higher frequency noise can make sound appear more detailed and/or lively in a way similar to a small amount of hiss on FM radio actually making for a more involving sound. Also, lowering the overall noise floor will mean that low level detail is no longer masked.
    But can noise create a dip in a frequency range, depress the bass for example, or can it only add to the treble which gives the effect of creating a dip by comparison?
    Lastly, how does this relate to a second PSU for the PI? I would guess adding a second PSU reduces the load on the first and also reduces the load on the on-board DC-DC converter but at the same time introduces a second potential source of noise. Is there a theoretical ideal here as to whether two supplies should be better or worse than one in the specific PI2AES design concept?
     
  10. JonnieD

    JonnieD Acquaintance

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    Here's an update on my Pi2AES, which I received at the weekend.

    Firstly regarding power requirements and supplies, mine was one of the newer 24-48V versions, as stated on the PCB by the power input socket. Interestingly, mine does not power up with a laptop supply with 19.1V output. The Pi3/Pi2AES just will not boot, I tried a couple of times, and with another supply. On my supply which is two large 12V car batteries, at 22.7V (discharged somewhat) it booted fine. However when the batteries dropped down to 18.7 it also would not boot it up once I had reconnected it! A 28V SMPS with 1.25amps also had no problem getting it to boot. My set up it just the Pi3B / Pi2AES powered together, and nothing else.

    So I'd be keen to hear Michael's feedback on this and if that's what he'd expect given the new regulators he's using.

    Secondly, a few words on the sound quality using the Pi2AES running with the batteries. Overall it does sound superb and I'm very pleased with it indeed. That's using my office set up with a Yggdrasil which has the most inputs of all my commercial DAC's so was a good reference to use. Sound quality of the Pi2AES is a step up from using either USB (G5 board) or Coaxial input both from a Squeezebox Touch / linear supply. The improvements are in micro detail, sound staging where its clearer, more delineated and layered front to back than the other transport, and sibilance especially on vocals are smoother (a lot better compared to Coax). And I don't know how to describe it in detail but the Pi2AES does seem more dynamic too, making it more attention grabbing to listen to.
     
  11. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    This is a bit concerning. You should not have had any issue with the 19V supply, but I am not 100% sure that it wasn’t something to do with your supply. Obviously I do not have that supply here so I cannot say for sure. I guess at this point I can only state that 24V is what people should run and anything less is potentially problematic.

    I certainly encourage everyone to give me feedback on any issues that you have regarding the power supplies.

    Michael
     
  12. JonnieD

    JonnieD Acquaintance

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    Thanks Michael, I appreciate the fast feedback and comments.

    I will try another 19V supply also, and let you know. I need to make up an adapter for the other I have with the correct plug for the Pi2AES. One of the 19V supplies that wouldn't boot I did subsequently test successfully on a PC, which also has a 3.5" disk, and those are quite heavy on start up current. So I don't think its current related, but maybe voltage on the Pi2AES? Certainly the car batteries once they'd gone down to 18V would still have been capable of many amps of current.

    As I say, I'll keep you posted, obviously if there's something that's just up with my set-up I don't want to alarm others who have one or are considering buying.
     
  13. Biodegraded

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    That's the MCTH PS, I'm guessing? Did you compare how it sounded with that vs the batteries (or anything else)?
     
  14. JonnieD

    JonnieD Acquaintance

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    Ha, well deduced, it was the MCTH PS!

    I've got so much kit here, I seem to have several PS's at each voltage ready to try though not all connectors are the same. I've just done a bit of soldering though to overcome that.

    I did do some comparisons, albeit briefly, and the main difference I could tell was that the batteries provide a cleaner sound, with blacker background. That's consistent with other battery vs SMPS or linear PS I've tried in the past. My main DAC is battery powered too, and that has been proven many times to better any mains PS I've used.
     
  15. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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  16. Jnslvb

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    Months ago, as solution I went for a stacking header to provide ampler air flow volume inbetween the Pi and header for bigger heat sinks to the Pi processor and usb controller and mini fan. In doing so had to modify the Pi2AES casing, and it worked pretty well. Then after sharing the issue of USB controller overheating and my DIY'ing to Michael Kelly, he advised for an external powered HDD rather than using the Pi's usb power to unburden it's usb controller. Which got me to go for a DIY external powered usb cable. And today everything works as a charm, where I can even leave the mini fan unpowered. In this scenario I'm using fully the USB data output. Hope this sharing can help some. [​IMG] [​IMG] [​IMG]
     
  17. weaver

    weaver New

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    Any news on how this RJ45 board is coming along Michael?
    I currently have my PI2AES sat on an Allo USBridge Sig (their take on an ultra low noise Pi using a Pi compute module). So far, swapping to this from a standard Pi has been a bigger benefit than any of the power supply variations I have tried (including using Allo Katana for the Pi power supply). So I would now really like to get a single ethernet cable between PI2AES and the external DAC and eliminate the ribbon cable and extra junction.
     
  18. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    The PCB's are here and I am hoping to get 10 of them built this week before my production guy goes on vacation. I'll need to put some in the store so you can buy them. I've decided to set the cost at $25 plus shipping. That way I can ship them to you guys with tracking.

    Michael
     
  19. Michael Kelly

    Michael Kelly MOT: Pi 2 Design

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    BTW, Since I do not have a Metrum DAC I have no way to test, other than giving them a good visual inspection. So, once again dear friends, you get to be my Guinea Pigs!

    Cheers,
    Michael
     
  20. weaver

    weaver New

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    Just some visual reminders of the actual module and also to confirm the assumption that the output will be for standard ethernet patch layout rather than cross-over layout? (I have already confused myself once over this using a male RJ45 connector to 8 pin connector which didn't work whereas a female RJ45 to 8 pin plus an ethernet cable did)
    [​IMG]
    [​IMG]
     

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