Hi Guys,
 
As a Hardcore Gamer , I am Involved in sound systems just for few days and according to Mad Lust Envy's Gaming Headset Review and My Budget I got my brand new AKG K702's. And while continueing my research to get the best "mostly competitive" sound quality from my headphones , I discovered DAC's. First of all , are they usefull for gaming ?, or maybe should I use an AMP or soundcard for better sound quality? The Major problem is , as mentioned in the Gaming Headset Review , AKG's have a really good positioning(the reason I bought them) and I don't want the positioning performance to be effected by the DAC/AMP or soundcard. I am using a desktop , so it does not matter whether it is a Desktop or Portable DAC/AMP. My budget is around 300 - 400 $ , but I may expand it a bit. I want to drive this headphone at full capability.One last question , Is it possible to use the DAC and the Soundcard at the same time , and is it usefull for competitive gaming? Sorry if I had spelling mistakes  and Thanks for Your Replies

Anybody , please reply. I have limited time to make a decision.

You would be better off buying a high quality soundcard than a dedicated DAC. A DAC has none of the features needed for competitive gaming. I would look into buying a Asus Xonar Essence ST/STX, Phoebus, or Creative Titanium HD. All three of those cards will have the sound adjustments, Dolby headphone, and other gaming features that you will not get with a DAC. The DAC chips in those cards, are very comparable to most DACs in the $300 price range. 
 
If you are looking at a good amp to go along with your sound card, look into the Matrix M-Stage. It has been reported to combo very nicely with the AKG K702. 
 
Good luck!

Hello and welcome, 
 
 A dac/amp is more oriented to music listening, in your case i'd get something like a soundcard (you can use it as a dac) and a headphone amp to drive your K701's to full potential. It will be something like: 
Soundcard > Headphone amp
 
Another alternative is to buy the Astro mixamp, and connect it to a headphone amp. 
 
Source > Mixamp > Headphone amp
 
By doing that, you wont lose the mixamp dolby processing for games. 

I would recommend the Titanium HD as well.  Then run RCA out to a cheaper amp like an o2 or Magni.

Try to get the lake people v100 used.