front panel sound

Discussion in 'Asus' started by Randy Davis, May 7, 2006.

  1. Randy Davis

    Randy Davis Guest

    I have the a8n5x. I have sound through my regular speakers, but I wanted to
    connect a front panel sound for headphones and mic. I have pulled the
    jumpers from the motherboard and plugged my front panel connectors in. Sound
    plays from regular speakers and when I plug headphones in it stops but I
    cannot hear it in the headphones. Is there something else I should set or

    Randy Davis, May 7, 2006
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  2. Randy Davis

    grumpy Guest

    From memory you can use the front OR rear connectors but not both.
    grumpy, May 7, 2006
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  3. Randy Davis

    Randy Davis Guest

    Well, if that is true, then I am unable to use the front. Based upon what
    you are telling me, when I hook up the front jacks the sound from the rear
    jacks should be dead. It isn't. It still works When I plug in my headphone
    or speakers to the front jack I get no sound from either the rear jacks or
    the front jacks. Obviously, I should get sound from one or the other.

    Randy Davis
    Randy Davis, May 8, 2006
  4. Randy Davis

    Paul Guest

    On the ALC850, the Front_Out and the Surround_Out, have a 20 ohm,
    50 mW amplifier on them. (If the amplifier is enabled, that is
    strong enough to drive headphones.) The Amplifier in each case can
    be enabled or disabled. If the Amplifier is disabled, the output
    impedance increases to greater than 600 ohms, which is weaker.

    A 20 ohm output, can drive a 32 ohm headset.

    A 600 ohm output, will be squashed by a 32 ohm headset.

    To get full signal level, the output impedance of the driver has
    to be lower than the load impedance.

    Amplified speakers have an input impedance of 10000 ohms, and
    draw virtually no current at all from the audio connection.

    If you connect a 32 ohm headset, and a 10000 ohm amplified speaker
    input in parallel, the result is slightly less than 32 ohms, which
    will still squash a 600 ohm output.

    So, the question in your case is, are the amplifiers inside the
    ALC850 enabled or disabled ? Telling the software that you
    have headphones connected, is probably the only evidence of
    an amplifier in the software interface.

    Your front panel wiring is probably connecting BLINE_OUT_R to
    Line_Out_R and to the headphone jack in the front of the case.
    With that wiring, both the front and rear ports will be
    wired in parallel. If you plug headphones in the front, and
    amplified speakers in the back, both are operating in parallel.
    If the Amplifier in the ALC850 is disabled, the loading of the
    headphones squashes the signal. If you can manage to get the
    Amplifier enabled, the ALC850 should be able to drive the
    headphones and the amplified speakers at the same time.

    If you are attempting to use un-amplified speakers, the 4 or
    8 ohm loading of un-amplified speakers is too much for that
    kind of chip.

    In the Realtek Audio Control Panel, tell the software that
    you have headphones connected to the Line_out, and in
    theory, the software should turn the amplifier on for
    Line_out. Line_out is the green connector.

    Paul, May 8, 2006
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