PC to External Sound Card to DAC?

Hello.

I don't have direct experience with any of those products, but since you are not getting any replies, here are my thoughts as tips/guidelines.

Adding a card is generally a good idea, but Creative doesn't make audiophile-type kind cards, to my knowledge. A SotM or PPA (Paul Pang Audio, a Korean enthusiast with a strong following in the computer audio community) would be more like it. A clean power supply to the card is also a significant upgrade, generally a linear power supply.

Been looking around but can't find if the USB input to the D1 is synch or asynch.
If synch, the the computer clock is in command. Bad news. An audio card with a very good clock should make a big difference.
If asynch, the DAC clock is in command, which is better generally speaking. Still the D1 gets its power through the computer USB, again, bad news. That power is more than likely noisy. Look into iFi products, especially the iUSB to provide clean power to your D1 through USB.

Look into computeraudiophile.com as well. A forum more focused on what you are after. Be prepared to be overwhelmed at first, but you'll get past it.

Good luck!

I use the ESI Juli@ sound card and it is awesome.

Maybe this is a dumb question, but what makes the Juli@ so good, the quality of the digital output? I understand that Bryston uses the Juli@ in its BDP-1 player and it is reportedly a first rate transport.