Isn't most Audio-GD gear tuned around the HD600's? They always seem to match really well with them. I know my Audio-GD ROC (discontinued balanced amp) sounds great with my HD600. It drives them with absolute ease and the sound is so open. Too bad they discontinued it, as well as the SA variation. Great amps.
Also the NFB12.1 is a great amp/DAC for the money. Easily bests Little-Dots OTL offerings. It also have more than enough voltage and power for the HD600.
Not sure if they tune for it but I love my HD600 with the Audio-GD FUN. Easily drives them to ridiculously loud levels with ease.
I've commented before I personally prefer the HD600 over the HD650. I enjoy having the best of both worlds a neutral open can with incredible details and when I want a more "dynamic" sound I just slap on the Denon AH-D7000s and go to town.
Here's them chilling together. For me...audio heaven :)
Edited by N0sferatu - 1/30/12 at 4:41pm