Do-it-Yourself S/PDIF Coax Connector

This is just a quick little hack that I did on my MythTV box some time ago. The motherboard that I have did not come with a cable for the S/PDIF audio output and it would have been $10 – $20 to purchase one. So, I did some searching around and found out it is actually quite easy to make one myself.

This particular motherboard has a three pin header that actually allows a coax or optical out. The coax connection is easy enough, if I needed optical out I would just buy the cable. The pin-out of the board looks like this:

For a coax connector, you just need the SPDIF_OUT and Ground pins. The +5V is only used for an optical connection. So, with the parts I had lying around, I found an RCA jack, metal bracket, connector and some wire. The connector I had was actually four pins, but I was able to cut off one of them. It did not have any keying on it, so it is possible to insert it backward, so I just had to be conscious of that when plugging it in. Then, nothing fancy, I just wired it up. The SPDIF_OUT pin goes to the tip connection of the RCA, the Ground goes to the ring. Here are a couple pics of how it turned out. I’ve been using it for a while and it works great!


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5 Responses to Do-it-Yourself S/PDIF Coax Connector

  1. Don George says:

    Would you happen to know what the wiring would be for the optical output. Must need some kind of coax to optical converter?

  2. Jason says:


    In this case, you would not need a coax to optical converter. It would be possible to directly connect an optical transmitter to the motherboard. I did a little bit of searching, and I think something like the Toshiba TOTX142L(F) part would work. It is available from DigiKey for $5.

  3. Timothy Day says:

    Thanks for this. Works perfectly with the Intel Atom 330 motherboard and Apex Mi-008 case. There is even a spot at the back of the case to fit the SPDIF jack!

  4. winz says:

    Just great, I’ve need to do this for ages and now i found this post, Great Work 🙂

  5. sathish says:

    would it work if connected directly to rca input of home theatre system.

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