plumschnaps

https://www.youtube.com/watch?v=zswXWHqzFkM

https://www.youtube.com/watch?v=XZ9jTpl503k

Got a pair of Sennheiser HD6 Mix today. I've got an Asus Xonar AE sound card, wich supposed to support 150 Ohm headphones. So far I like the sound, but I would like to try other options as well. The OP-amp is replaceable. Is there anything I should try in regards of just replacing the amp? How much room for improvemet I have, before switching to more serious external amp? Thank You in advance!