I recently purchased a surround sound stereo system and wanted to connect my computer system to it. I knew there was a SoundBlaster® Live 5.1 with digital outputs and wondered if my SoundBlaster® Live Value was capable of producing digital output. My SoundBlaster® Live Value has a digital output connector on it but I was not sure what signals were on it, or for that matter, where I could get a mating connector for it. I noticed that in the User's Guide that there was an AUD_EXT connector on the card that had S/PDIF outputs and inputs. I decided to see if I could interface these to the outside world. I started searching the internet and came up with a lot of information on building an interface, and to my surprise, information on how to get Dolby® Digital out of my card as well. The following is what I did.
First, I converted my card to a SoundBlaster® Live 5.1 using information found here. The process was fairly easy for me since I am an electronic tech and I have all the equipment required, including a good soldering station which made the desoldering and soldering a breeze. I used the Realtek RTL8029x method for programming my chip, it was the easiest method for me since these cards are readily available used.
Below is the pinout for the AUD_EXT connector on the SoundBlaster® Live Value where the S/PDIF I/O is located, the schematic for the interface, and a parts list. Portions of the schematic were borrowed from drawings found elsewhere on the internet. The pins I used are 1 and 2 for +5 volts, 7 and 8 for a ground, 15 for S/PDIF in, 17 for S/PDIF out (Front) and 23 for enabling the S/PDIF in on the mixer volume control. Pulling pin 23 high through a 4.7k ohm resistor tells the SoundBlaster® Live cards that a LiveDrive® is connected (I think), enabling the S/PDIF input in the mixer volume controls. It may enable or change the other things in the cards software/drivers. I would show you how my interface looks, but I don't have a digital camera to take a picture of it. It is basically 2 RCA jacks on a card slot blanking plate, a circuit card mounted on the plate with all the components and a 40 pin header, and part of an IDE ribbon cable connecting the SoundBlaster® Live card to the interface.
|AUD_EXT connector pin assignments|
|1 VCC||+5V power supply|
|2 VCC||+5V power supply|
|4 AC97CLK||24.5 MHz clock output|
|6 GP_SPDIFIN#2||SPDIF input signal|
|9 SPDIFO#3||SPDIF Out signal (Rear)|
|10 GPO1||General Purpose Output #1|
|11 GPO2||General Purpose Output #2|
|13 GPO0||General Purpose Output #0|
|15 GP_SPDIFIN1||SPDIF Input signal|
|17 SPDIFO#0||SPDIF Out signal (Front)|
|19 SPDIFO#1||SPDIF Out signal (Center/Sub)|
|22 SPDIFO#2||SPDIF Out signal (Mix Front/Rear)|
|23 GPI0||Digital Input, (GP Input 0; Reserved)|
|24 GPI1||Digital Input, (GP Input 1; Reserved)|
|25 OUTMIDI||MIDI Output|
|27 INMIDI||MIDI Input|
|31 ADCSDO2||I2S audio data input 2|
|33 ADCSDO1||I2S audio data input 1|
|35 ADCSDO0||I2S audio data input 0|
|37 I2SCLK||I2S serial bit clock|
|39 I2SFS||I2S Frame sync|
|Misc Parts||2 RCA connectors
1 40 Pin Header
40 Pin Ribbon Cable
No special software is required for this modification. Everything should be included with the drivers for the card. There are a few things to note though. If you want the Dolby® Digital 5.1 audio passed through to your external equipment, disable the AC-3 decoding in the AudioHQ control panel. Be sure to select 5.1 speakers in the AudioHQ mixer as well. UPDATE: If you use PowerDVD XP build 2417, all channels may be present on the output of the interface, not just the front channel. I don't know about other software DVD players.
This seemed to work well for me, I hope you have the same luck as I did. And please, don't fry your card, or yourself attempting this. If you find any blatant mistakes, please let me know. Good Luck.