2010 Mac Pro front panel audio wires (44 pin connector) question.

[Laverda]

Hi all,

Currently working on making this work in Win10 (or work at all) on an Asus H410M-E motherboard installed in my Mac Pro case, which is a former A1289 model from 2010. This gives a front panel with power on/off; power led; front audio jack; 2 x USB 2,0 and 2 x Firewire 800.

Currently trying to make the front jack socket work.
When I am looking at the 44 pin cable, there are 6 cables all set together ina separate insulation, so I guell they are the audio related oens. This is also how at least 3 of them are designated in other members work f this 44 pin connector.

So, working with that 6 wire assembly, I started out by connecting a black wire (the fully insolated one) from the 44 pin connector to the MB fp header GND (HD audio).
Then I used the grey wire from the Mac Pro fp 44 pin connector to the right channel on the mb fp header.
And finally a brown wire from the Mac Pro fp 44 pin connector to the mb fp header.

No sound.

Looked in Win10 in audio and there's only a rear jack registred. I did open the headphone line in a separate window.
No sound.

So, I then connected a purple wire from the Mac Pro fp 44 pin connector to sense_send on the mb fp header.
No sound.

I then connected a green wire from the Mac Pro fp 44 pin connector to "sense_return2" on the mb fp header.
No sound.

I also switched these two green and purple wires around.
No sound.

I twisted the whole cableset to isolate from noise.
No sound.

I then made a shield with tin foil for the whole length of my homemade audio cable. Uses the last unisolated black thin wire on the Mac Pro 44 fp connector.
No sound.

I have the idea the the wires on the Mac Pro 2010 (A1289) front panel audio consist of a total of 6 wires, as they are isolated together when looking at my spare fp 44 pin cable:

- black. May be ground (gnd).

- black. May be ground (shielding).

- grey. May be right channel.

- brown. May be left channel.

- purple ? (may be sense send?).

- green. ? (may be sense return?).

Further, when I am looking at an Intel HD audio explanation, the last pin is called "pressense", but has nothing to do with ausio as such. Intel explains it as this: "Active low signal that signals BIOS that an Intel® HD Audio dongle is connected to the analog header. PRESENCE# = 0 when an Intel® HD Audio dongle is connected".

I understand that Intel moved from AC97 to HD aduio to overcome some problems that AC97 may have presented, such as fewer channels (stereo) and sometimes cracks in speakers because of how the connections are made/function, plus the improved jack retasking abillity. They may have lowered the nosiefloor as well, but I did not look into that thoroughly yet.
The improved jack retasking is interesting, because it can redirect for example a microphone inserted into a headphone jack, to be a microphone jack. This is done by using a variety of resistors that represents various things inserted into the jack socket. Smart. But in my win10, there's only a microphone detected, not a headphone. Hmmm.... Strange.

Further still, for HD audio, Intel designates three pins to microphone: pin1 (mic left) and pin3 (mic right, and finally pin6 (sense_return1 - the mic).

Following this, the sense function on the motherboard is clearly pin7 (sense_send) when inserted, and when removed it must be pin10 (sense_return2).

When I am looking at Intel's description of the old AC97 audio, some of the pins are the same:
left, right and gnd.
The remaining are still used for mic, pin4 is also described as an audio ground, and pin7 (sense_send in HD audio) is described as "Filtered +5V used by analog audio circuits". As I read my motherboard manual, I don't have an AC97 function, only HD audio. Some older boards can toggle between these two setuo, but it would appear, that mine cannot (2020 model motherboard).

So, my questions are these:

- What does Apple use those two wires coming to the front panel 44 pin connector for: the green and the purple?

- Does Intel HD audio always require a "sense_send" and eventually also a "sense_return2" wire to be present (connected)?

All inputs and ideas are most wellcome, as I am a little out of ideas!!

Kind regards,
Laverda.

 

[Laverda]

Update:

Now I have managed to make the sound work from the front panel audio jack for headphones.
The basic 3 cables were good, but there must ahve been a flaw in the audio driver; as I installed a new driver, I got a Realtek audio software panel which allows me to enable the front jack.

So the last question is now answered: no, there's no absolute need for sensing wire(-s) to enable audio out on the front jack with HD Audio. It will jsut require a manual switching between the rear and the front jack.

I still need to make the jack detection work propperly so that it close off the rear I/O panel sound, when a front jack is inserted.

So, I still could use som info on what the green and the purple wires coming from the 44 pin front panel in audio relation is for?

More over on my own build thread.
Kind regards,
Laverda.