I just connected my new Rega DAC to the computer via USB, it popped up in the sound settings, and choosing it there directs sound to it just fine. What confuses me, however, is that it says "Analog Output". What does that mean in this context? I suppose the output must really be digital, since it works when it's connected to the digital input on the DAC, right?
Sorry if this is a stupid newbie question, I'm very far from an expert on Linux audio stuff, but I'm going to start learning, so I hope you can help me.
By the way, do I understand correctly that what I am communicating with in the sound settings is the ALSA layer?
UPDATE: I have withdrawn my accept for one of the answers, because that answer made me believe that it didn't matter whether I chose the “analog” or “digital” version of the output. I recently realized that, although I still don't quite understand why and how, there is a difference after all, at least for the S/PDIF connection that I am now using instead of USB. I wrote this blog post about it.