I had promised to contribute a guide about how to utilise the Digital output header on some motherboards, if one didn't have the output module. The module is not commonly available.
Note that this will give you a coaxial output. For optical, you're pretty much on your own. You will need to buy an optical transmitter, and supply both SPDIF and power to it (all available off the same connector, btw). This is not tackled here because I've not needed to do it, but advanced users can figure this out on their own.
The good news first. The motherboard header uses 2.54mm pitch connectors, which is the same as analog audio connectors on motherboards and soundcards - used for connecting CD-audio and Auxilary audio connections.
Since Windows 98 we have not needed the analog audio connectors, so we will re-deploy them to deliver digital output from motherboards.
[BREAK=Warnings, Disclaimer]
Now the bad news. You need to solder some connections. If you don't know how to do this, you have to get someone to do this for you along with these instructions. TV repair shops are a good bet.
NOTE: The quality of your digital output is variable. Bits are not bits. A cheap chip may resample all audio, poor implementation can screw up the output quality including pops and clocks. THIS CONNECTOR WILL NOT CURE THESE DEFECTS!!!!! It just provides a connection method, and does not improve quality of the digital output. Also it does not add capabilities of your motherboard's audio. If DTS connect is not available, resampling will happen. Questions like 'will this support my motherboard?' are going to answered by a 'I don't know'. Do your research on the motherboard first, then post.
On with the guide!
[BREAK=SPDIF Header. Read this, or DIE!]
Figure out the pinout of the SPDIF header. The motherboard SPDIF header has three pins (signal, ground and +5V) with a dead spot for one pin. So the 4-pin CD-audio connector fits perfectly. Note: the connector will work when correctly inserted only one way. I can't stress this enough. The red pin on the connector must mate with the SPDIF out on the header. It's quite possible your pinout is reversed, in which case two pins of the connector will hang off the header edge in mid air. This is fine. Connecting the system with the +5V feeding into the digital input of a receiver will result in a destroyed speaker or receiver, and maybe damage the motherboard.
This one is for the Asus M2A-VM, a very common motherboard. Most Asus boards will follow the same format. You should be able to find the pinout on the board manual. Here the connector will overhang the header, since the signal pin is pin 3. In cases where the signal pin is pin 4, the connector will fit the right way around. In case of complex motherboard headers, you've to locate the pinout yourself - such as the Jetway boards.
[BREAK=Beg, borrow, steal!]
We will need to:
1. Get an analog audio connector. These are usually supplied with your CD-Drive or DVD-drive, and remain in the box forever, or get thrown away. This is what it looks like:
2. Get an RCA female cable connector. You can use a panel connector as well, but then you need somewhere to fix the panel. There are a few in this pic, ranging from 10 bucks to 100 bucks each.
[BREAK=Opening, cutting and other nasty stuff]
3. Open the RCA connector. This is an inside view. The 'signal' pin carries the 'hot' end of the signal and the 'ground' pin is the return or ground. Technically the signal flows both ways.
A quick note: RCA is a connector. It can carry any electrical signal - audio, video, digital, speaker output (in some cheapo systems). It's just a metal piece and does not discriminate and cannot distinguish between signals. Somebody had an argument with me that the SPDIF connector can carry 5.1 and this one cannot. That's BS. SPDIF can travel over RCA, TOSLINK, BNC, and even twisted joints. BNC is the most efficient, RCA is inferior to it by a country mile but is decent enough for compressed audio streams. They are independent of each other.
Don't skimp on the connector, get the best you can afford. The cheap ones will tarnish and lose (and loosen) connection over time. A decent Neutrik will cost 100 rupees, and last a lifetime.
[BREAK=prep]
4. Prep the wire. We will cut away one end of the connector, then strip away some insulation at the end, and chop off the white wire. Now we have the exposed signal and ground wires.
[BREAK=Putting it all together]
5. Solder the wires to the RCA conn. Remember, Red to center, black to body. THIS SHOULD NOT BE REVERSED. EVER. Use flux along with solder to burn off oxides and create a better joint. A good iron always helps. Don't be scared of too much heat, it's less damaging than a cold joint. 5 seconds should get everything hot for a good joint.
Here's a finished connector.
It's done a little differently, so don't worry if yours end up looking different. After soldering, you have to use the stress relief to clamp the whole wire down. This will ensure the connector can take a bit of abuse without stressing the wire.
[BREAK=Finishing]
Pass the wire through the connector barrel BEFORE you solder, or you won't be able to close the connector. Use a bit of tape or strain relief on the other end (the audio connector) for strain relief.
6. Enjoy the music. If you enable digital output and use the header, you now have a coax digital connector for yourself. Should take 15 minute tops.
Note that this will give you a coaxial output. For optical, you're pretty much on your own. You will need to buy an optical transmitter, and supply both SPDIF and power to it (all available off the same connector, btw). This is not tackled here because I've not needed to do it, but advanced users can figure this out on their own.
The good news first. The motherboard header uses 2.54mm pitch connectors, which is the same as analog audio connectors on motherboards and soundcards - used for connecting CD-audio and Auxilary audio connections.
Since Windows 98 we have not needed the analog audio connectors, so we will re-deploy them to deliver digital output from motherboards.
[BREAK=Warnings, Disclaimer]
Now the bad news. You need to solder some connections. If you don't know how to do this, you have to get someone to do this for you along with these instructions. TV repair shops are a good bet.
NOTE: The quality of your digital output is variable. Bits are not bits. A cheap chip may resample all audio, poor implementation can screw up the output quality including pops and clocks. THIS CONNECTOR WILL NOT CURE THESE DEFECTS!!!!! It just provides a connection method, and does not improve quality of the digital output. Also it does not add capabilities of your motherboard's audio. If DTS connect is not available, resampling will happen. Questions like 'will this support my motherboard?' are going to answered by a 'I don't know'. Do your research on the motherboard first, then post.
On with the guide!
[BREAK=SPDIF Header. Read this, or DIE!]
Figure out the pinout of the SPDIF header. The motherboard SPDIF header has three pins (signal, ground and +5V) with a dead spot for one pin. So the 4-pin CD-audio connector fits perfectly. Note: the connector will work when correctly inserted only one way. I can't stress this enough. The red pin on the connector must mate with the SPDIF out on the header. It's quite possible your pinout is reversed, in which case two pins of the connector will hang off the header edge in mid air. This is fine. Connecting the system with the +5V feeding into the digital input of a receiver will result in a destroyed speaker or receiver, and maybe damage the motherboard.
This one is for the Asus M2A-VM, a very common motherboard. Most Asus boards will follow the same format. You should be able to find the pinout on the board manual. Here the connector will overhang the header, since the signal pin is pin 3. In cases where the signal pin is pin 4, the connector will fit the right way around. In case of complex motherboard headers, you've to locate the pinout yourself - such as the Jetway boards.
[BREAK=Beg, borrow, steal!]
We will need to:
1. Get an analog audio connector. These are usually supplied with your CD-Drive or DVD-drive, and remain in the box forever, or get thrown away. This is what it looks like:
2. Get an RCA female cable connector. You can use a panel connector as well, but then you need somewhere to fix the panel. There are a few in this pic, ranging from 10 bucks to 100 bucks each.
[BREAK=Opening, cutting and other nasty stuff]
3. Open the RCA connector. This is an inside view. The 'signal' pin carries the 'hot' end of the signal and the 'ground' pin is the return or ground. Technically the signal flows both ways.
A quick note: RCA is a connector. It can carry any electrical signal - audio, video, digital, speaker output (in some cheapo systems). It's just a metal piece and does not discriminate and cannot distinguish between signals. Somebody had an argument with me that the SPDIF connector can carry 5.1 and this one cannot. That's BS. SPDIF can travel over RCA, TOSLINK, BNC, and even twisted joints. BNC is the most efficient, RCA is inferior to it by a country mile but is decent enough for compressed audio streams. They are independent of each other.
Don't skimp on the connector, get the best you can afford. The cheap ones will tarnish and lose (and loosen) connection over time. A decent Neutrik will cost 100 rupees, and last a lifetime.
[BREAK=prep]
4. Prep the wire. We will cut away one end of the connector, then strip away some insulation at the end, and chop off the white wire. Now we have the exposed signal and ground wires.
[BREAK=Putting it all together]
5. Solder the wires to the RCA conn. Remember, Red to center, black to body. THIS SHOULD NOT BE REVERSED. EVER. Use flux along with solder to burn off oxides and create a better joint. A good iron always helps. Don't be scared of too much heat, it's less damaging than a cold joint. 5 seconds should get everything hot for a good joint.
Here's a finished connector.
It's done a little differently, so don't worry if yours end up looking different. After soldering, you have to use the stress relief to clamp the whole wire down. This will ensure the connector can take a bit of abuse without stressing the wire.
[BREAK=Finishing]
Pass the wire through the connector barrel BEFORE you solder, or you won't be able to close the connector. Use a bit of tape or strain relief on the other end (the audio connector) for strain relief.
6. Enjoy the music. If you enable digital output and use the header, you now have a coax digital connector for yourself. Should take 15 minute tops.
