The AC97 connector is spliced/wired into the HD Audio connector which allows the option to use one or the other audio format. I'm looking for such a cable. I'm trying to avoid having switch out the whole front panel assembly. The audio cable in the case being used only has the HD Audio connector. There is no spliced AC97 connector. Realtek HD Audio Drivers is a software package for Realtek High Definition audio codec. This will enable your computer to communicate with audio devices such as speakers and sound cards. It is important to have a 64-bit version of a Windows operating system installed in your computer before downloading Realtek HD Audio Drivers x64. The front panel audio header on an Intel® Desktop Board lets you connect to a front panel audio module built into a system chassis. See the header pinout configuration below for connecting a chassis with Intel® High Definition Audio (Intel® HD Audio) or AC'97 (Audio Codec '97) audio.
The Problem
Recently I've bought a new sound card which is capable of encoding Dolby Digital in realtime through the optical output. I've decided to go for the Creative X-Fi Titanium PCI Express. After reserving an interrupt for the PCI-Express slot in the BIOS I've finally managed to install drivers under WinXP. Plugging the headphones in I run into the next problem. The headphone plugs on the front panel doesn't work anymore. After a short search I've found the reason for it. Intel has released a new connector standard for front panels called Intel® High Definition Front Panel Audio (also called Azalia). This pinout is now used by all new soundcards. The bad thing is that this new connector is said to be pin compatible and they even have the same missing pin. But in fact they are not compatible.
HD Audio for onboard is fairly new, but it's intended to replace the (craptastic) AC97. You only need to use one or the other; it's not intended for you to use both.
AC97 loops the headphone signal through the front panel before it goes to the rear connector. If you connect a headphone to the front panel this loop is opened. This simple wiring has the only disadvantage that the signal goes through the whole PC case if you connect speakers at the rear jack.
In the new Azalia standard the front and rear jacks are not connected in series but in parallel. The soundcard must either provide an additional output or a switching mechanism. Additional signal lines for jack detection notifies the soundcard when headphones are connected. How the jack detection is treated will certainly depend on the soundcard and it's driver. In my case the X-Fi Titanium turns off any output to the front panel if the jack detection is left open.
The Solution
Ac97 Header
If you need only the jack at the front panel you can solve this issue by soldering a simple adapter. This adapter will loop through headphone and microphone channels and shorting the jack detection pins. This adapter is put in between the AC97 front panel cable and the Azalia connector on the soundcard. Doing so, the soundcard alway sees headphones connected to the front panel and will activate this channels. In my case the optical output at the rear panel is still functioning which is all I need.
Hd Audio To Ac97 Adapter Hdmi
The Adapter
Since all the audio pins are at the same position I've decided to solder a male and female connector together directly.
I've pulled out all pins except of the audio channels from the male connector. You can see the remaining pins in the following picture. 2 pins for both headphone channels, 2 pins for the mic and 1 pin ground. Before soldering both connectors together I've soldered a small wire to connect pin 7 and pin 10 at the female connector. To solder the connectors the single pin in the upper row of the male connector has to be bend a bit.
That's all. Plugging it onto the Azilia connector on the soundcard and then connecting the AC97 cable of my front panel solves the compatibility issue.