External DAC for Sony PS3

Note: This was also posted on the Home Theatre forum.

I own a Linn 2-channel (stereo) music system that is in the same room as my 50-inch HDTV plasma TV. While saving up for a true home theatre set-up, I would like to use the music system for better sound when viewing movies on my plasma.

Would anyone know if I can connect a PS3 to an external DAC like the Benchmark DAC1 (digital optical connection) and in turn connect the DAC to my music system (analog RCA)? This would allow me to "see" the movie on my plasma via HDMI and "hear" the movie via my music system (volume set to off on the plasma).