So I received my Zero Dac/Amp (upgraded version from wsz0304) 2 weeks ago after reading glowing reviews on here. I connected it to the laptop via optical. The Zero might not have the best amp but, after reading all this talk about how the HD600s needed to be amped, I was expecting to be blown...

Hey guys, I'm new to the Head-Fi and the whole audiophile world so go easy on me . I keep going in circles over what circumaural open headphones to get that would sound good without an amp. I narrowed it down to the HD595, AD900 and HD600, but if you could suggest some more, that would be...