ASUS Xonar Essence STX

Wish I had something to compare to. Had an audigy 2 for years and thought extension was better in treble. But Audigy 2 does not have a headphone amp and cannot push the HD650 properly. Not even sure it can push the AKG Q701. The HD600 with the audigy 2 are fantastic since HD600 does not need a headphone amp. I am a pretend to be audiophile since I have a limited budget.
 
Althought I do have tons of headphones: I ripped all music to wav file using EAC. I feel at times I need a headphone tube amp to improve sound. When I tested my STX against a Sony 400 disc CDplayer to receiver, both sounded exactly the same. So I stuck with the STX and ripped the CD collection to WAV.

Bought Sony MDR XB1000s almost a year ago and they've been great. A mate of mine bought a soundcard and reckons it made a big difference and convinced me to buy one. I read into reviews, and they said that this was a good card for headphones, and they are bang on. It always felt like there was something missing when i first listened to my MDRs, and i kinda felt ripped off after upgrading from MDR XB700s but this card truly justifies the upgrade. I have a modern motherboard ( MSI GD65 8D) and the audio quality increase this card gives over my mobo soundcard is staggering. Max volume increase this card gives is just crazy. HQ audio is completely flawless; no signs of clipping even at max volumes. First impressions were amazing, and it still continues to amaze me.

Installation for me was a hassle; power supply really has to be jammed in there for it to work and when it eventually did, the drivers gave me the ****s (I am running windows 8, maybe compatibility issues) and telling me to make sure the card is properly installed etc etc. but after trying a few downloaded versions from asus website, it finally worked.

However, the better the audio equipment you have, the more difference you will notice. I use my Astro A40s for teamspeak/skype and my Sonys for me-time, and the difference I find is MUCH greater on the Sonys than it is on the A40s

To sum this up, best $170 I have spent on this computer. 100% reccommend it for people who truly appreciate music and have a good pair of headphones.

I don't really have anything to compare this to, since this is my first non-board soundcard (some might say I took quite a leap) To be honest, I wasn't even expecting that much of a difference on the price, since I'm used to seeing components paying way more, but the quality of the STX really blows me away! The headphone amp is something that could be better, my only other amp is a measly Pro-Ject headbox S, which performs pretty close to the xonar, although being slightly warmer and not as detailed, also I don't really like how it sounds on your general every day 32 ohm gaming headsets, or my 55 ohm akg k121's. The Xonar is a great sound processor though, in fact it's so detailed that it made me realize that I need a better speaker amplifier to keep up with it
 
TL;DR Great (value) DAC, decent head amp for 250ohm or above headphones