Hi,
I'm hoping someone here can help me.
I want to use the Front panel Audio Connector on my A7V8X-MX
motherboard but the cabling from the front panel is confusing me.
The designations on the FP cable are, from right to left as follows:
L-Out,
R-Out,
Gnd,
Mic In L,
Mic In R,
Gnd.
Can someone tell me which cable goes to which pin on the motherboard
Front panel Audio Connector? I realise that I need to remove the links
but from there I'm uncertain of which wire needs to go where. Will
this enable me to use headphones which interupt the rear speakers?
In terms of the logic at work here, a 1/8" stereo plug has three contacts
called "tip", "ring", and "sleeve". When connected to a stereo output
these are "Left", "Right", and "Ground". When used for a monophonic
electret or passive microphone they become "Mic-In", "Mic-Pwr", and
"Ground". That is how I arrive at the connectivity shown below for the
three microphone wires. In the figure below, the bias or Mic-Pwr
is joined to the Mic-in inside the microphone itself.
http://www.epanorama.net/circuits/dynamic_to_electretinput.html
+------+ / \
| |-----------+---------------- audio --------| |
| |mic+ | \ /
| mike | | +===+
| | +-------------- bias +5V -------| | 3.5mm plug
| | |===| to soundcard
| |mic- | |
| |------------ ground -----------------------| |
+------+ | |
+=======+
| |
Also, since your front connectors don't have any return lines, when you
remove the two jumpers and connect the six case wires, there will only
be audio out on the case front connector. The back connector will no
longer work. (A muting function won't work unless the case has return
wires to connect to the two BLINE signals.)
FP_AUDIO (rotated 90 degrees CCW wrt pic in manual)
Mic In L -------> MIC2 AGND <------> MIC GROUND
Mic In R <----- MICPWR +5VA
R-Out <---- Line out_R BLINE_OUT_R
NC
L-Out <---- Line out_L BLINE_OUT_L
The NC pin stands for "No Connector", as in don't connect anything.
The +5VA is an auxiliary supply for a headphone amplifier, a function
that is hardly ever used. Note that MICPWR is a 5V supply as well, but
it has a current limiting resistor, so it is safe to short MICPWR to
ground by accident. It is not safe to short +5VA, as it is wired
directly to the +5 supply - it is a "hard" supply and you should be
careful not to connect anything to it.
HTH,
Paul
