Help with PC Audio Quality vs. CD

I hope someone with real experience can help out with this. I am having a hard time getting the same quality sound from a PC that I get from a CD player. I recently built a HTPC running Windows MCE and ripped all my cd's using lossless compression. I'm using an M-Aduio Audiophile 192 sound card and run a coax digital out of the PC to an external DAC and to my amps. It just sounds flat to me, not that it's not clear sounding, but the bass is weaker, I can hear a harshness that's not there if I run any old CD player to the DAC through the same connection. Has anyone else experienced this? I keep reading in this forum that people are saying how much better the computer transport is in theory, but I have yet to witness it. I heard that the Windows KMixer is the problem. I tried ASIO and Kernal Streaming drivers that are supposed to bypass this, and it sounds clearer, but still not as 3-dimentional and "black background" as a CD player (and I mean ANY cheap CD player, I've tried 3!)

Can someone out there with an external DAC try this and let me know their results? Use a DVD player or anything with a digital out... I don't get it. My soundcard alone cost 3 times as much as the cheap DVD player I tried and it doesn't sound as good. Anyone experience this or have any suggestions?

Here's my system so you can understand the sound I'm looking for.

I have an external MSB Link DAC III Full Nelson that I've been using for years and I really like the sound of it. I've been using a couple Sony CD changers and running them to a MSB Digital Director that will automatically switch between digital inputs, out to the DAC, then to a tube pre and tube power amp (modded dynaco ST70) and out to a pair of Monitor Audio GR10's. This system (with the right tubes) sounds so sweet to me. I'm into the huge soundstage, crisp, smooth sound - melty mid-range... you know, the analog tube sound!

I have experience in recording studios and work professionally in computers, so I have a good understanding of both, so don't be afraid to get technical with me. Any help would be greatly appreciated!!

Ben