Thanks for your responses.   I also had a feeling there wouldn't be a substantial improvement, because the k550 doesn't necessarily need an amp as you pointed out. Maybe I'll check the nano idsd for its dac, to improve the sound on speakers, and send it back if i don't hear a perceivable...

Hi    First of all, great website, and thanks to all users for sharing the knowledge and opinions, really helpful.   Maybe you can be of some help : I'm wondering whether I should upgrade to a new dac/amp combo on my system.   Currently composed of these elements :        - dac/amp combo...