TTL S/PDIF to Coax adaptor

This is a simple circuit that you can use to connect your motherboard's digital audio out to your stereo receiver. Supposedly, I can buy one off ASUS for my motherboard, but I couldn't find one in stock -- and it only took about 15 minutes to makes (if you have enough stuff lying around).

 

Schematic

 

Motherboard Connection

You can see the SPDIF_OUT connector on the center bottom of the screen. The connector on my motherboard was a standard .1" pin spaced header with numerous outputs - I only needed the TTL output and the GND signals.

 

Completed Device

I was able to fit the few passive components into the RCA shell (I used both surface mount and through hole). I should have taken a picture before I applied the glue gun glue all over it, but it wasn't all that pretty. The orange cables runs to my Marantz receiver, and it works great.