Sound Card? Pre amp?

I just picked up a used delta 66 (or was it 44) with a breakout box on ebay for 99 dollars. I love it. The breakout box has two mic preamps and two more line ins for 4 track simultaneous recording. I go into the line in with a dmp3 and it sounds great. The end. But I recorded with an x-fi soundblaster for a few years, and it's also perfectly fine.