How is the volume? Can it go loud? 

Hey!   Can you please tell me how loud is the MA900? Currently I use an ATH M50, and I like its loudness. I want to try open cans, but without loosing a lot of loudness. Would the Sony suit me? 

I have heard that it is supported, but I wonder what functions can I use. Any experience?

Thanks for all the input. I will report back after my new soundcard (hopefully with a better D/A converter) and headphone amp arrive. Oh by the way I know it is not an audiophile solution :) but I have tried to increase the highs with an EQ, and I really liked the result.

Wow, thanks for the quick reply guys! Yeah, I think I will not ditch them so easily. I have searched the net quite thoroughly, an came to a conclusion that an Audiotrak Prodigy HD2 DE soundcard + a Matrix M-Stage headphone amp would be a good "bang for the buck" combination for the HD650.

I know buying headphones without trying first is stupid, but I got a good offer, so I could not resist... My other headphone is an old AKG K66. When I first tried it, I was prepared to experience something better, but the sound of the 650 really disappointed me. Compared to the K66, the...