HiFiBerry Digi+Pro to Gungnir

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by colorsquid, Mar 8, 2017.

  1. colorsquid

    colorsquid Friend

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    Hi Team,
    Im using the HiFiBerry Digi+Pro to feed all S/pdif inputs to my Gungnir MB. The Toslink optical output direct to Gungnir works great, no problem. The minute I use Coax or BNC, and switch source resolutions, the buy better gear light of the Gungnir kicks on. Could this this be a galvanic isolation or grounding issue? The Digi+Pro transformer jumper does nothing, and the RPI 2 is grounded at HDMI level. BTW, USB works great.

    Has anyone been in my footsteps before?
     
  2. yotacowboy

    yotacowboy McRibs Kind of Guy

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    How are you feeding the Digi+Pro? Ethernet, WiFi? And, what player?
     
  3. Kattefjaes

    Kattefjaes Mostly Harmless

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    Are you using a 75 Ohm SPDIF cable or just a random audio RCA cable?

    Also, try not doing anything extra to ground the Pi, and opening the jumper on the Digi+ Pro.. you may be causing grounding problems rather than improving matters.
     
    Last edited: Mar 9, 2017
  4. colorsquid

    colorsquid Friend

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    Thanks guys,.

    Running this endpoint with Roon via ethernet only, no WIFI available n the RPI2. I work in a pro video environment, so I know both RCA and BNC cables are 75 ohm dielectrics.

    I am powering the HiFiBerry Digi+Pro with 5V direct on P3. I will make sure that both Gungnir Multibit and HiFiBerry are on the same power strip when I get home.

    Since both the BNC and RCA are electrical outputs, and the S/pdif works fine, this had to be a galvanic isolation issue, right?
     
  5. Kattefjaes

    Kattefjaes Mostly Harmless

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    Could be.. With the jumper closed, as it's shipped, there's a high resistance to ground over the SPDIF, suitable for DACs that aren't grounded, and float, like the Modi Multibit. Open it for something like a Gungnir Multibit that is properly grounded, and you get the benefit of the galvanic isolation.

    https://support.hifiberry.com/hc/en-us/community/posts/207749389-HiFiBerry-Digi-Pro-beta-test?page=3

    Also, do try not grounding it via the HDMI while you're at it, if just opening the jumper doesn't help. We all know what utter bastards grounding problems can be, to the point of being somewhat counter-intuitive on occasion.
     
    Last edited: Mar 9, 2017

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