Recording line input to USB via D/A?

Hi all,

What I need is one, really good analogue line level input to my computer's USB-port. There are lots of USB-based audio interfaces out there (transit, M-audio, etc.), but most of them have a plethora of different kinds of inputs and outputs, or seem kind of low-end, which makes me sceptical of the quality of their A/D-conversion.

My question is: can I get higher audio quality simply buying an A/D-converter with a line input, then converting its pdif-signal to USB? What would I need for the latter part (pdif to USB)?

I've been looking at the ART DI/O tube ADA. Also, there's what seems to be a fairly stereohile-oriented product called X2, its from an Italian company called purebits. You can check it out at

I'm completely new to this place, so forgive me if my question is kind of off-center. Any input appreciated. Thanks a lot in advance.

The ART DIO has a good rep. I use a Waveterminal U24 for USB to PCM output--ignoring the A/D. The U24 also seems to have coax and toslink inputs. You might start with the U24 and then see if the ART makes an appreciable difference.
Honestly, if recording is your bag, talk to the people at Not sure what you're using this for or what features you need, but there's an awful lot more than Transit and M-Audio on the market.