May I ask as to why? I am curious as to how DACs can have a market when they have no real addition value (at least in my price range). Is it all just Placebo?
If it's the DAC chip itself, most of them - properly implemented of course - can measure flat. The problem is the part of the circuit after the DAC - either they have a crummy output stage or some brands deliberately color the sound there, which is where it gets tricky, because people will either hear little difference because there's no tonal difference (and they can't hear the smaller improvements in detail, timing, etc) or they will rave about how much better it is when in fact it is EQ-ing the sound. Case in point - I tried a few CDPs, one of them getting rave reviews for headphone users, when I had a Burson Soloist review unit (to compare to my Cantate.2 in terms of transparency), and all of these had serious issues ranging from too dark/warm sound off a $1,000+ CDP to a lauded budget CDP turning the drummer into Mr. Fantastic. People call that "wider soundstage," but it's clearly not accurate when the rest of the band is generally in their proper place in front of your forehead but the drums go around the head like he has arms that stretch towards where the audience is. My Meier Cantate.2's PCM2702-based 16-bit DAC (this chip is used as a USB receiver in other DACs) had a more natural sound stage and more neutral tone than all these other CDPs. In fact, surprisingly enough, the only one I liked was the Cayin CD-50T, which actually used tubes but sounded more neutral (if a little "sweeter" in the midrange) than nearly all the other solid state CDPs, but I wasn't into spending $1,100 on a CDP and have to swap out the tube at some point when I can just get a music server with a decent analog output like the Aune S1 (not locally available though but I'm waiting for some upgrade-itchy audiophiles to sell theirs on the cheap). For DACs specifically they seem to be less varied than these, but some can still seem off - like the HDP, which has a too warm lower midrange used as a DAC, and if I plug my headphone into it, the bass drum hits and bass guitar slaps end up with some over excursion on the driver.
In the case of your computer I'd bet on the real problem,
if any, being the output stage designed for driving an earphone, not like they would really even design it to do that well with 2.1 speakers.You can try the Schiit Modi - at $100 you can get a decent DAC circuit (assuming your USB port can run it properly - some don't produce enough power and some home made PCs and even laptops get noise through there) and when you compare just make sure you match the output levels. Full Windows volume with a DAC, then match that with using an analog cable from the laptop to the amp.
In my case, just eliminating that annoying mix and match of preamped line level signals out of a computer headphone output is just enough reason to get a cheap but relatively good DAC if my amp didn't have one. I do enough gain matching/leveling on my car set-up, but at least there after one afternoon it's set for the next few years until I replace anything.
