This is probably a beaten to death issue, but I am a guy who has Airport Expresses all over his house and I'd like to upgrade the quality at a few of the locations where my nicer rigs are. The airtunes feature works surprisingly well, but the sound quality is just acceptable - and is a bit of a downer on my Rotel, Adcom and Creek rigs.

Has anybody improved the sound quality by getting a DAC between the airport express and the preamp?

If so, what are the DAC's that yielded the best results?

Much thanks in advance.