Quote Originally Posted by treclol View Post
I have the HD600 myself. You can't run them without an amp. I run them with an Asus Xonar Essence One - it's an external DAC and headphone amp that sits on my desk. Not only can it drive the HD600, it also works as a dedicated sound card, and it's often reviewed as the best DAC you can get on a PC. Highly recommended.
By non-audio professionals, sorry to burst your bubble. Go to head-fi.org and say that there and you'll get laughed out the door!

Also, the Xonar Essence One is quite a bit out of the OP's price range, anyways.