The Shanling ph100 is a great amp for the AKGs. Tons of detail, great bass extension and impact and a build quality unlike anything I have seen. I recently bought an M-stage with the opa627 mod hopeing it would be an upgrade for my k701s, but after comparing the two I feel like the ph100 is probably as good or better. The o2 is a good amp for the price as well, but I thought it was a little to dry and lifeless with the k701s. Still might be worth checking out if accuracy is what your after.
Edited by nickwin - 2/16/13 at 10:25am