Connecting Enermax front panel audio to Asus A7V600-X

Discussion in 'Asus' started by forumposter32, May 23, 2005.

  1. Well, I’m just gonna throw that out there because there may or may not
    be someone on this site who knows this. Anyway, the ends of the cable
    say this:

    EAR R (two of them)
    EAR L (two of them)

    On the motherboard, the manual says I have on the front panel audio:

    Line out R
    Line out L

    I’m not sure right now how to match those. LOL, I’m glad it’s not
    crucial to my system.

    BTW, I just ordered an Enermax noisetaker power supply. Does anyone
    know if that power supply will be incompatible with my mobo?
    (That’s in Canadian dollars.)
    forumposter32, May 23, 2005
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  2. forumposter32

    Paul Guest

    The only thing questionable about the supply, is whether the retaining
    latch of the 20 pin part, of the "20+4P" connector scheme, will latch
    to your board. Latching securely is important, to prevent damage to
    the connector if the connectors become slightly loose and ohmic.
    Connectors can "walk apart" through thermal cycling, unless a latch
    is there to secure them. A working latch is just good insurance.
    Otherwise, the supply looks OK.

    Here is your wiring:

    MIC_DATA         MIC2  x   x  AGND         GND
    MIC_VCC       MICPWR  x   x  +5VA
    EAR_R Line Out_R  x   x  BLINE_OUT_R EAR_R
                      NC  x
    EAR_L Line Out_L  x   x  BLINE_OUT_L EAR_L

    Based on the wiring type of your front panel wiring,
    the rear Lineout connector will not be muted when you
    plug in headphones. Both the rear amplified speakers
    plugged into the Lineout connector, and the headphones,
    will be working at the same time.

    Paul, May 23, 2005
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  3. forumposter32

    Paul Guest

    On closer inspection of the Tigerdirect info and the Enermax info

    I wonder if I have the right Enermax part ? The Tigerdirect table
    of power ratings shows no split +12V output, and Tigerdirect says
    the power supply has a -5V output. The Enermax table shows the
    output doesn't have -5V, and there are two 12V outputs (one for
    processor, and one for disk drives and the rest of the motherboard).

    While the missing -5V is normally not a problem, I seem to remember
    some accessory device used -5V. Possibly some brand of motherboard
    has a dependence on -5V, but I cannot track down where I saw a
    reference to that.

    Paul, May 23, 2005
  4. Thanks, I’m glad I ordered a pair of speakers that allow me to hook up
    the headphones to the speakers and mutes them.

    Well, I’m curious since I have two EAR_R and EAR_L, do I put the black
    ones on the BLINE_OUT or the colored ones?
    forumposter32, May 24, 2005
  5. forumposter32

    Paul Guest

    One style I've seen, looks like this:

    Front_Panel_Assembly -------- wire-----EAR_L ------ EAR_L

    In this case, the two EAR_L are shorted together. In that case,
    it doesn't matter which one goes on which left channel pin.
    Such an assembly does not support rear speaker muting when
    headphones are plugged into the front.

    If the two EAR wires on a channel are separated wires,
    then one is an input (like the Line_out_R)
    and one wire is an output (like BLINE_OUT_R).
    But, if you had this style of hardware, the EAR
    wires would have an IN and OUT specified. If they
    are labelled with exactly the same thing, then
    they must be the same signal.
                                                   |           |
                                         ----------|   Sound   |
                                         |         |   Chip    |
                                         |   ------|           |
                                         |   |     |           |
                                         |   |     |           |
        Case Front Audio                 |   |     -------------
        ("Interrupting" Type Jack)       |   |
                                         |   |
        -------- 1     AGND        (in)  |   |             Green Lineout (Back)
        |   ______ 2   Line_out_R <------    |
     - -|  /  ^                     (out)    |         AGND --------->+ (SLEEVE)
     |  |     |--- 3   BLINE_OUT_R ---->---  |  ------------------->+ (RING)
     |  |                                    |                        
     |  |      |--- 4  BLINE_OUT_L ---->---  |  ----------------->+ (TIP)
     |  |      v                             |
     - -|    \_____ 5  Line_out_L <----------

    How muting works in the above diagram, is when headphones are
    plugged into the left hand jack, the 2-3 and 4-5 contacts go
    open circuit. That breaks the audio connection to the green
    Lineout connector on the back of the computer. In your case,
    your front panel wiring is more likely to look like this:

                                                   |           |
                                         ----------|   Sound   |
                                         |         |   Chip    |
                                         |   ------|           |
                                         |   |     |           |
                                         |   |     |           |
        Case Front Audio                 |   |     -------------
        ("Non-Interrupting" Type Jack)   |   |
                                         |   |
        -------- 1     AGND        EAR_R |   |             Green Lineout (Back)
        |   ______ 2   Right <-----+----    |
     - -|  /                       | EAR_R  |         AGND --------->+ (SLEEVE)
     |  |     +------  |  ------------------->+ (RING)
     |  |                             EAR_L  |                        
     |  |       +------  |  ----------------->+ (TIP)
     |  |                          | EAR_L  |
     - -|    \_____ 5  Left <-----+--------

    In the above figure, it doesn't matter with EAR_R goes to which
    pin, as they are shorted together at the case front assembly.
    There is no muting function, because there are no contacts on
    the jack that get opened when the headphones are plugged in.

    Paul, May 24, 2005
  6. forumposter32

    Fred Aspect Guest

    Thanks Paul. That's a lot of good info. So in the latter situation (ie
    front panel lacks muting functionality), is there any loading issue
    when, say, I wish to use listen to music on my headphones whilst
    speakers are plugged in to the rear connection (but not turned on)?
    Basically, I did not hook up my front connection because I was worried
    about loading issues when operating earphones and speakers in parallel.


    Fred Aspect, May 24, 2005
  7. forumposter32

    Paul Guest

    Computer headphones are supposed to be in the vicinity of 32 ohms
    load. I have seen a sound chip with 32 ohm output drive and
    also one with 20 ohm output drive.

    This page shows some sample amplified computer speakers. Input
    impedance is listed as 5K or 10K ohms.

    To compute total load, when two devices are in parallel,
    a handy formula is R1*R2/(R1+R2). If we put two 32 ohm
    sets of headphones in parallel, 32*32/(32+32) =32*32/64 =16.
    If we put headphones and computer speakers in parallel, then
    it is 32*5000/(32+5000) = 31.8 ohms, which is hardly
    any change at all. Compared to the headphones, amplified
    computer speakers are no load at all. So, it is safe to run
    computer speakers and headphones at the same time. With
    two sets of headphones, the result is lowered output sound
    level from both headphones.

    Note that, on a typical older 5.1 computer sound chip, the
    main stereo output channels have 32 ohm drive, intended to
    run headphones from the chip when it is set to two channel
    (stereo) mode. The other four channels, (surrounds, center,
    and sub), tend to be 600 ohm output impedance, which is a
    lot weaker. The 600 ohms works fine with the 5K or 10K of
    the amplified computer speakers, but won't be a good match
    for 32 ohm headphones.

    Paul, May 24, 2005
  8. forumposter32

    Fred Aspect Guest

    Hey, thanks Paul. That really does help. I will run my front audio in
    parallel. Many thanks,

    Fred Aspect, May 24, 2005
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