Crudo20,
I have no doubt that the digital output from the Airport Express will be perfectly faithful to the digital data that it receives from a PC. The analog output, however, is unlikely to be as top notch as you might get with an expensive DAC or CD player, but probably good enough for most needs; like feeding various built in speaker zones in a "smart" home (I use my Airport Express to feed a Russound Amp in my utility/boiler room, which feeds five separate house zones).
I have no doubt that the digital output from the Airport Express will be perfectly faithful to the digital data that it receives from a PC. The analog output, however, is unlikely to be as top notch as you might get with an expensive DAC or CD player, but probably good enough for most needs; like feeding various built in speaker zones in a "smart" home (I use my Airport Express to feed a Russound Amp in my utility/boiler room, which feeds five separate house zones).