USB DAC on a laptop

So it is gonna convert a lesser analog headphone signal from your built-in card to digital, then back into analog and then boost the signal.  The fidelity will be less after another round of ADDA and, at best, you'll send the same lesser signal to your headphones. While there may be some volume advantage with a stronger amp, it is the same quality signal (at best) that your built-in card gave you since that is where the signal still originates from. 

Ah... Wait a minute... I just googled audioquest dragonfly and all is clear now. Sounds interesting and might indeed work, but I am assuming that you would have to set it up to work as an audio device just like any USB audio interface

Real good headphones might expose the deficiencies of the onboard D-A. Not attempting to be an audiophile snob, but I think there is quite a significant difference between the audio outs of my laptop and my audio interface. The difference may be less noticable if the source is compressed radio ready sound. I suspect the $1 converter on board is probably optimized for that source. When the source is raw vst or unprocessed audio I think the difference in quality is undeniable.

 
Thanks for the responses everyone, some very interesting insights.
 
From the AudioQuest site, here's the blurb:
 
"Launched in 2012, press and public alike have enthusiastically embraced AudioQuest’s multi-award-winning DragonFly USB digital-to-analog converter/preamp/headphone amp as the rare audio product that bridges the gap between die-hard audiophiles and mainstream music lovers.
DragonFly plugs into a computer’s USB port to bypass the computer’s compromised audio circuitry and deliver cleaner, clearer, more naturally beautiful sound to headphones, powered speakers, and complete audio systems. Small, affordable, easy to use, and remarkably effective, DragonFly was named Stereophile’s 2012 “Computer Audio Component of the Year” and 2012 “Budget Component of the Year;” Tone Audio’s 2012 “Digital Product of the Year;” Computer Audiophile’s 2012 “Computer Audiophile Product of the Year;” AudioStream’s “Greatest Bits;” and What Hi-Fi?’s 2014 “Product of the Year.”
 
@ Kev999 . . . you are correct, I was mistaken, it doesn't plug into the headphone jack, it's a USB device, so there must be drivers to install . . . if it truly bypasses any computer's audio circuitry, isn't it just another audio interface ? . . . except when you're actually recording, it must still be routed through the computer's main audio interface.
 
@ filtersweep, synkrotron, and AT . . . I definitely hear a difference plugging the headphones between my USB Audio device, as opposed to directly into the laptop headphone jack . . . it wasn't a cheap laptop, it cost around $2500 CDN, so I was expecting the audio components to be half decent, but it seems I have to customize it further for serious audio, since this laptop was not originally "designed" for audio work.
 
@ Cactus Music . . . guess I'll just have to take my laptop and some of my mixes to the retailer, and actually hear the difference. I'm curious to see how the sound is altered by this device, and whether it's an accurate reference for monitoring the projects.
 
The headphones I use are KRK KNS-8400 . . . so not top of the line, but still $300 decent.
Of course, I use this laptop for mobile recording and composing . . . I still only trust my main studio desktop system for final mixes.

Thee are at least 3 interfaces that come with decent ASIO drivers for $100.  That was going to be  my first response, but I understand people not wishing to drag around a 2 lb box. 
I take my Scarlett with me if I'm going to do anything critical. But as I said, there absolutely nothing I notice wrong with any of my laptops headphone jacks... sound just fine to me.. 
 
That little USB dongle looks like it would be OK but I'll only pay $29 for something like that as I would say it's all hype. $150 gets you a heck of a lot more with a small interface. 

noynekkerit wasn't a cheap laptop, it cost around $2500 CDN, so I was expecting the audio components to be half decent, but it seems I have to customize it further for serious audio, since this laptop was not originally "designed" for audio work.

Wow! yeah, I've just checked the exchange rate and that is, indeed, an expensive laptop. I agree with everyone that, for music creation, you need a proper ASIO interface. 
 
That said, I listen to music through my laptop headphone jack all the time, and the sound is excellent, in my opinion, although I would never use it as my Sonar sound device.
 
cheers
 
andy

tlw
Don't forget to buy some Audioquest USB cables to go with it, their very, very expensive audiophile USB cables really massively improve digital audio. Just like their $1,000+ mains leads do.

Apparently.

TLW, sarcasm recognized and appreciated . . . I'm also starting to see this device as audiophile overhype.
 . . . though, it's just across the bridge, and really I must go have a listen.

The Mobil UA from Roland is what i use for cours and on the go : unbeatable sound quyality (32 bits resolution ) and drivers latency imprssive (the only usb card that i succed to go Under 64 samples of buffer size via usb) and i own RME and other great stuff ;)