JustBoom DAC Zero

  • I just got my JustBoom DAC Zero and installed it on my Pi Zero. When I switch to the DAC as the audio output, it blanks my TV (hooked up over HDMI). I'm running LibreELEC v7.90.010.

    It seems these guys got it working:
    Streaming Media with JustBoom Audio HATs - Maker Space

    But I can't confirm the version. I did add these lines to my config.txt:


    And the device shows up under audio output options (obviously, I'm switching to it when the display goes out). Anyway, I was wondering if anyone was successfully running this configuration.

    FULL DISCLOSURE: I have shaky hands and may not have done an amazing job soldering my 2x20 header. This absolutely could be my own fault.

    I did grab the debug log:
    LibreELEC DebugLog for MagnaVis - Pastebin.com

    Here is a log of a successful boot into the GUI when the card is removed:
    Ubuntu Pastebin

    Thank you all for your hard work and time on this amazing project, and for helping me! =D

    Edited once, last by MagnaVis ().

  • I did see the thread, but it was for the Digi, not the DAC. Support for each will be different, and I did not want to assume that support for the DAC was included with support for the Digi.

    I also looked through the comments on the GetHub page for the 7.0 branch, and none of them specifically mention this device.

    This is why my question was more in regards to if anyone else had it working rather than "can you help me, this isn't working." My assumption, if I had to make one, would be that it's working for most people without issue. Then I would know it was me, not LibreELEC, and would redo my solder job.

  • The should definitely not blank the display when playing audio through the DAC Zero.

    Could you try it without this setting in the config:


    I don't think it should need that to operate, and perhaps is what is causing the issue.

    Then you should be able to go to the LibreELEC menu and select the audio output as in this image - screenshot011.png

    On a side note, we are going to try and replicate the issue tomorrow, and see if we can find anything (when I am back at office - as don't have a Pi Zero at home)

  • Update 31-01-17 - We have carried out a series of tests and managed to replicate the issue.
    LibreELEC -> Raspberry Pi B+ -> DAC HAT No issues
    LibreELEC -> Raspberry Pi B+ -> DAC Zero No issues
    LibreELEC -> Raspberry Pi Zero -> DAC HAT Blank screen
    LibreELEC -> Raspberry Pi Zero -> DAC Zero Blank screen

    Other Kodi based OS are working fine with all of the combinations above.
    This happens when selecting the card under Settings - Audio, the screen goes immediately blank despite the rest of the system being still up and running. No changes with or without dtparam=audio=off.

    Can somebody from LibreELEC please help?

  • Unfortunately I don't have a RPi Zero (they still seem to be impossible to get) so can't test myself.

    Could you run a test with the latest Milhouse build? LibreELEC Testbuilds for RaspberryPi (Kodi 18.0)
    Testing with a kernel 4.10-rc Milhouse build would also be interesting LibreELEC Testbuilds for RaspberryPi (Kodi 18.0)

    If they also fail please post the output of tvservice -s before and after the display blanks and please also post the dmesg log after display blank.

    so long,


  • I can test with the other kernels this weekend if this isn't resolved by then.

    Thanks JustBoom for confirming the issue! You guys have a great product, and I can't wait for it to be working with LibreELEC.

  • @ HiassofT - sure thing, we will perform those tests tomorrow and report back with results once done.

    We've got a few Pi Zeros kicking around if that would be helpful to you?

    I can test with the other kernels this weekend if this isn't resolved by then.

    Thanks JustBoom for confirming the issue! You guys have a great product, and I can't wait for it to be working with LibreELEC.

    Thanks very much - glad you like it and appreciate the kind words :-)

    Hopefully with the help of the fantastic LibreELEC team we can work out the issue pretty quickly! More testing tomorrow :-)

  • The 7.0.3 build on the downloads page (downloads – LibreELEC) is working fine in all tests.

    Seems this is just an issue introduced by the latest Kodi/LibreELEC updates. Not that this helps the OP who is trying to use 7.90.010, however, just thought it may help to isolate the cause of the issue.


  • Yes sorry - it's down for planned maintenance adding additional storage, unfortunately this is taking a little longer than the expected ~1 hour. Hopefully it will be back soon!
    Server is now back online.

    Edited once, last by milhouse ().

  • Good to hear the latest beta is working fine!

    BTW: 7.95.2 is in the queue and should be released soon, if anything breaks please drop us a line - every feedback is highly appreciated!

    so long,


  • Just finished testing with #131 and #130 as advised above.

    They both were updated from 7.0.3 and they both worked fine.

    Unfortunately after a bit that I wasn't using the interface the screen blanks again. This is only happening if the JustBoom card is stacked on the Raspberry Pi Zero. This new problem happens with #131, #130 (20170130225444) and v7.95.1 BETA.
    As far as something is playing or I use the interface all works just fine.

  • Thanks a lot for testing!

    I've been in contact with popcornmix, he could reproduce the issue and told me Phil Elwell will have a look at it. Something really strange seems to be going on with the RPi zero - it's almost identical to the RPi1 B+ so it's rather puzzling why the RPi1 works fine but not the RPi0.

    I'll keep you posted if I hear of any updates on that issue.

    so long,


  • I had a few minutes to play with the new build, 7.95.2. I see the same issue with the screen blanking after idle time.

    What I found suspicious was the short duration of time. I timed it, and it was almost exactly a minute. Under the audio settings is the "Keep audio device alive" setting, which defaults to one minute. I changed it to two minutes and tested again. The time to blank the screen moved to two minutes. When set to always, I haven't seen the issue occur, and I've been running it for a good while now. The screen does go dim, as expected, and can be 'woken' from the dim screen, as expected.

    Thanks again!

  • Thanks a lot for the feedback!

    MagnaVis  JustBoom could you run a test with my 7.0.3 build with Cirrus Logic audio card drivers?

    This build is official 7.0.3 version plus kernel 4.9 (as opposed to 4.4 in official 7.0.3) plus drivers for the cirrus card (the latter shouldn't hurt you in testing).

    I'm suspecting it could be something in the kernel, quite a lot has changed between 4.4 and 4.9. For example 4.4 includes an additional patch to the I2S driver that's not in 4.9 - not sure if this could be the culprit
    bcm2835-i2s: Reduce the TX DREQ threshold · raspberrypi/[email protected] · GitHub

    so long,