The Razer Barracuda AC-1 (CMI8788/Oxygen HD audio controller) carries a 10-pin front panel audio header labelled J26 on its PCB. This connector is not a Razer-proprietary interface; it implements the industry-standard AC97 front panel audio header defined by Intel in the Front Panel I/O Connectivity Design Guide (order number A29286-001, October 2000). The header is a 2×5 arrangement on a 2.54 mm pitch, with pin 8 absent as a mechanical key to prevent reversed insertion. Any AC97-compliant front panel cable from a standard PC chassis is compatible with this header.
| Pin | Name | Description |
|---|---|---|
| 1 | Mic Input Signal | Front panel microphone input signal (biased when supporting stereo microphone) |
| 2 | Analog Ground | Ground used by analog |
| 3 | Mic Power | Microphone power / additional MIC input for stereo microphone support |
| 4 | +5V | Filtered +5 V used by analog audio circuits |
| 5 | Right Channel Audio to front | Right channel audio signal to front panel (headphone drive capable) |
| 6 | Right Channel Audio from front | Right channel audio signal return from front panel (when headphones unplugged) |
| 7 | Analog Ground | Ground used by analog audio circuits |
| 8 | KEY | |
| 9 | Left Channel Audio to front | Left channel audio signal to front panel (headphone drive capable) |
| 10 | Left Channel Audio from front | Left channel audio signal return from front panel (when headphones unplugged) |
Signals
- Mic Input Signal — analogue microphone signal from the front panel jack; bias voltage applied for stereo microphone support.
- Analog Ground (pins 2 and 7) — dedicated analogue ground reference for audio circuitry.
- Mic Power — filtered supply voltage providing microphone bias; also serves as a second MIC input line for stereo microphone configurations.
- +5V — filtered +5 V rail powering front panel analogue audio circuits.
- Right Channel Audio to front — right-channel output from the mainboard amplifier to the front panel headphone jack.
- Right Channel Audio from front — right-channel return signal; when the front jack is unplugged this path is used to mute the rear panel output.
- KEY (pin 8) — this pin position is absent on the physical connector and serves as a mechanical polarising key to prevent incorrect insertion.
- Left Channel Audio to front — left-channel output to the front panel headphone jack.
- Left Channel Audio from front — left-channel return signal; used to mute rear panel output when a headphone plug is inserted at the front.
Notes
- The connector is a 2×5 header on a 2.54 mm pitch; pin 8 is physically absent (no pin) to act as an insertion key.
- Switching-type 1/8-inch (3.5 mm) ring-tip-sleeve mini-phone jacks at the front panel detect plug insertion via the return lines (AUD_RET_L/R).
- Intel’s design guide recommends a 10 kΩ pull-down on AUD_RET_L/R after the output capacitor to avoid floating signals when no front panel cable is connected.
- The signal path routes mainboard output through AUD_FPOUT_L/R to the front jack, with AUD_RET_L/R looping back to silence the rear panel when headphones are in use.