"Physical discs are so 20th century," I wrote back in 2006, when I began experimenting with using, in my high-end rig, a computer as a legitimate source of music. These days I rarely pop a disc into my Ayre Acoustics C-5xe^MP disc player, unless it's an SACD I want to hear, or a CD I haven't yet ripped into my library. But many audiophiles, even if attracted to the idea of using a file-based system as a primary music source, do not want a computer in their listening rooms. Nor do they want to be bothered by the fact that a computer demands too intimate a relationship with its user.