Slhijb:
Yes, your current plan is the best way to get all you can from the MP3s provided your sound card has a digital output. Some sound cards that have a digital output only have it in mini plug form, and not sure what digital cable would go from mini to RCA (certainly there is no fiber cable like that). What I would recommend, and am saving to do for my system, is buy a Creative Labs Audigy 2 Platnium sound card ($200) which has 24/192 DACS and also has a break out box (the Extigy will work but has 24/96 DACs) that allows for fiber or rca style connections. Then you can buy/use a quality cable to make the connection and preserve as much of the signal as possible as it travels from the PC to the DAC. I would also recommend using a fiber cable for very long runs and www.audioadvisor.com last I saw was having a major sale on AudioQuest fiber cables. I think they are 'good' cables.
Matt
Yes, your current plan is the best way to get all you can from the MP3s provided your sound card has a digital output. Some sound cards that have a digital output only have it in mini plug form, and not sure what digital cable would go from mini to RCA (certainly there is no fiber cable like that). What I would recommend, and am saving to do for my system, is buy a Creative Labs Audigy 2 Platnium sound card ($200) which has 24/192 DACS and also has a break out box (the Extigy will work but has 24/96 DACs) that allows for fiber or rca style connections. Then you can buy/use a quality cable to make the connection and preserve as much of the signal as possible as it travels from the PC to the DAC. I would also recommend using a fiber cable for very long runs and www.audioadvisor.com last I saw was having a major sale on AudioQuest fiber cables. I think they are 'good' cables.
Matt