|Originally posted by taoster
is there a difference between a DAC and an upsampling DAC?
Yes. A DAC just converts the 16/44.1 to analog. An upsampling DAC converts the (digital) 16 bit/44.1 kHz signal to a (for example) 24 bit/96 kHz signal, then converts it to analog. This makes it easier for the analog low-pass filter to deal with.
Now you may think to yourself, what's the point? You can't introduce information that's not there?
Ah, but you can.
As kelly likes to say it, it's not so much that the algorithm is introducing information, as it is getting "less in the way". It introduces fewer "nasties".
Take, for example, a 22 kHz signal. It basically looks like a square wave before the analog filtering. Upsampling will make it look more like a sine wave. The "corners" are less sharp.
The overall effect is a smoother signal.
As tuberoller said, and I too feel the same way, at this point, I wouldn't get something that didn't have upsampling. I'm at the point where I'm comparing upsampling algorithms (listening to the GW Labs DSP right now). I'm not sure I would go 24/192, now that I've already gone 24/96, but that's because I'm already most of the way there. We are definitely talking about "that last little bit" here. But to me, that makes all the difference in the world, especially in terms of long-term listening fatigue. (And I listen for hours at a time. At work, on a good day, I can go through a stack of CD's, one right after the other.)
Download this file
and read the second page, it explains it pretty well.
EDIT: I forgot to answer the implied question -- is there an audible difference between an upsampling DAC and a regular one? Well, yeah, sure, a well-designed DAC can outperform a badly designed upsampling DAC, but I haven't heard the latter.