Originally Posted by Komder
AD700s will be good enough without the amp...down the road you can get a sound card w/headphone amp or just a dedicated amp but that's an expensive hobby non the less
That's not even part of his question. He doesn't need an amp for AD700s nor did he even consider one.
He's considering whether he needs a sound card and how much does he have to spend on a sound card to notice a difference.
For gaming you most definitely need a sound card for the AD700s. A sound card was such a benefit for positional cues that comparing the two...night and day.
Music wise, I found the sound card gave the AD700s a "hotter" signal and clarity was also increased. Everything felt more alive and music in general sounded better.
I reckon almost any sound card over 30 dollars would benefit you from the Xtreme Music to the Xonar DG or higher.