For the price of an expensive cable to go from your headphone jack you could get an entry-level usb dac and a cheap pair of rca jacks and KILL the headphone jack option.
4 responses Add your response
Yes, you must kill the mini jack. For < $30, this will be a vast improvement:
Depending on your other components and/or DAC, you could also use the optical out, which might yield an even bigger improvement.
I use this type of set up for all my computers, both at home and in the office.
Moving up in price, you could try the Hagerman Technology interface box for about $150 (?)......
Finally, there seem to be more and more DACs which take a USB input directly.
What your doing works but is usually limited by the limited fidelity of most desktop sound cards.
For CDs, I would also recommend the increasingly popular USB DAC approach for best sound.
For certain networked music servers and internet sources (radio stations, etc.), A Roku Soundbridge with an Audioquest G-Snake mini phono to dual RCA interconnect and a broadband internet connection will take you close to the limit there in sound quality. The G-Snake alone could be a relatively inexpensive cable upgrade for your current approach as well that might help to some lesser extent.