MDP-HDMI No Audio from Headphone Jack

Discussion in 'MacBook Pro' started by Leaping Tortois, Sep 23, 2013.

  1. Leaping Tortois macrumors regular

    Oct 11, 2010
    Melbourne, Australia
    Hi all,

    I have a 2008 unibody MBP that I often connect it up to my TV. Until recently I used a Mini Display Port to DVI (Dual Link) adaptor, connected to a DVI-HDMI adaptor, and then HDMI cable to the TV. I'd then run a stereo cable from the headphone port to the TV for sound. The MDP-DVI adaptor recently broke so I got a new MDP-HDMI adaptor as I no longer use the DVI.

    Issue is that when I hook up the stereo cable from my headphone jack I get no audio on my TV. When I hook up the old DVI setup I do get audio, so it's not a TV or stereo cable issue. Only thing that's changed is the MDP adaptor.

    My MBP doesn't support audio out over mini-display port, but I can't help but think that this is caused by OSX (10.8) trying to send the audio signal through the mini display port because it detects a HDMI adaptor.

    Does anyone have any experience/ideas with this?

    Thanks for any help

    - Leaping

    P.S. Issue with the DVI cable was that it kept dropping the video signal, but would still work intermittently.
  2. sojay, Sep 23, 2013
    Last edited: Sep 23, 2013

    sojay macrumors newbie

    Oct 24, 2011
    Known issue

    My 08 mbp also had no audio from the headphone jack. There are many old threads out there about this. If what you have is the same thing, it is a hardware issue. Some have been able to fix it manually with a paper clip, but be careful. My whole logic board needed to be replaced. I can't remember if it was a recall issue or if I had it done under warranty, but it was like getting a brand new computer.

    P.s. do you see a red light in the headphone jack? If so, it's likely the same problem.
  3. Leaping Tortois thread starter macrumors regular

    Oct 11, 2010
    Melbourne, Australia
    Thanks for the response. I'm fairly certain it's a software issue because the headphone jack will work fine by itself, but more importantly, it works fine when using a MDP->DVI->HDMI adaptor chain, it's only when using the single MDP -> HDMI adaptor that I get no audio.

    No red light, so hopefully that means it's not trying to use toslink.
  4. priitv8 macrumors 68040

    Jan 13, 2011
    Then it's also not sending a digital signal!
    Don't you only get audio from TV or also not from headphones?
    PS TV-s usually need the analog audio in to be assigned to specific VGA, DVI or HDMI port. On Sony's there is only one HDMI (HDMI 4 if memory serves), that can be paired with analog audio input.
    So check your TV's instructions!
  5. takeshi74 macrumors 601

    Feb 9, 2011
    What audio device is selected in Preferences when connected?
  6. snaky69 macrumors 603

    Mar 14, 2008
    On some TV's you need to map the audio in port to a particular HDMI port, else the TV will be seeking to play sound through HDMI, which it is not getting.

    My guess is that is exactly what you're experiencing.
  7. Leaping Tortois thread starter macrumors regular

    Oct 11, 2010
    Melbourne, Australia
    Sorry for not replying until now, I haven't been home for a while.

    To clarify, the issue seems to be with the Mini-Display Port because if I use the following chain

    MacBook Pro -> MDP/DVI Adaptor -> DVI/HDMI Adaptor -> HDMI Cable -> TV (Audio using 3.5mm jack from MBP into TV)

    Then everything works perfectly. This means that it is setup with the TV correctly (audio input matches the video input). However when I use this chain:

    MacBook Pro -> MDP/HDMI Adaptor -> HDMI Cable -> TV
    (Audio using 3.5mm jack from MBP into TV)

    In this case the audio doesn't work at all. Audio output in system preferences is set to "Headphones (Headphone Port)."

    Because the setup works when using the MDP/DVI adaptor I know that all hardware is working properly which leaves only two options:

    1) The Mini-Display Port -> HDMI adaptor is faulty; or
    2) OSX software is has detected a HDMI connection and is attempting to send audio there, even though there is no hardware to support this.

    It could be a faulty adaptor, and when I get the chance I'm going to see if it works with a different computer, but that might not be for some time. I was just wondering if anyone else had experienced this, or knew how to work around it.

    Thanks for the replies so far. Really appreciate it.
  8. snaky69 macrumors 603

    Mar 14, 2008
    Not necessarily. Plug an iPod or something similar while you have something plugged into the same HDMI port, I could bet my house you won't hear anything.

    I'm convinced you need to play with the settings on your TV for it to work properly.
  9. Shaggymax macrumors member


    Jun 8, 2013
    Lancaster, PA
    This is not a software issue, it is hardware. I sold a 2009 MB and purchased a 2010 MB, that indeed physically supported audio via Mini Display Port.

    Good luck, cheers.
  10. Leaping Tortois thread starter macrumors regular

    Oct 11, 2010
    Melbourne, Australia
    You owe me a house :p I get video from the HDMI connection to my computer, and sound from the 3.5mm jack plugged into my phone.

    As I have mentioned before, I am well aware that the hardware only supports video over the MDP, however Mini-Display Port -> DVI -> HDMI works fine with audio over the 3.5mm jack.

    Thanks for all your help guys. I think that chances are there's something wrong with the adaptor, be it faulty or design, or there's something so esoteric with the software that finding a solution is unlikely. I'll just go and get another MDP -> DVI adaptor until I can afford a new MacBook Pro.

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