[Dumptrucker]

I will start with the obligatory "Hi I'm new here, and know nothing at all about anything." and I'll be happy to prove it, by moving to the description of my challenge.
I have a room downstairs I like to escape to now and again to listen to music and pm daydream. This room has a mini desktop (Dell optiplex 780) on which I run Ubuntu os, and store lots of music files.
This room also contains audio components I have scavenged throughout the years, such as a yamaha mx-600 amp and c-45 preamp with some AR 18s bookshelf speakers.
I currently have the puter hooked to the rest via an 1/8"- to rca- splitter, into the preamp. I realize this is a very less than ideal setup, given the crappiness of the stock audio output of the Dell Optiplex, but this setup  sounds really good with a cd player, with a noticable dropoff in quality and volume when switch to the computer as output.
Thus my question; If I use a digital to analog converter only, such as the Behringer U-Control UCA222 will there be significant improvement in audio quality? or do I need a usb soundcard (computer has no pci slots) to output to my preamp?
Any advice is so greatly appreciated.
Thanks

 

[Roseval]

The UCA222 is a usb soundcard.
 
A "normal" soundcard is a card you put in a PCI slot. It receives the digital audio over this bus. On board is a DAC (Digtal to Analog Converter) hence the output is analog.
 
A "USB Soundcard" is a USB receiver hence you put it in a USB connector of a host (PC).
The digital data is send over the USB bus. Again there is a DAC doing the conversion.

 

[Dumptrucker]

Thanks Roseval for the reply.
I suppose what im getting at is would there a noticiable difference in sound quality in using the UCA222 versus an 1/8" Y splitter with RCA ends, into the computers audio output jack, or is it just another means of connection?