pfff dude I have two iBasso Balanced Portables, and when I had my pb1 I had some moron Crank my pb1 to max voulume with my DT 880 600 ohm BALANCED... which means there was a chance he was shoving upwards of like 600mW into that thing >.> drivers are rated for 200mW max. I don't remember the sensitivity so HOPEFULLY he didn't wreck them but yea... I know the feeling, and for the record balanced amplifiers for the most part are more powerful than their single end counter parts, the new pb2 I got can run like 2.4w into 32 ohms, which means if I ran my D2k out of it on High gain... it would xPlode BUT the good new is the D2k is rated at about 2w! And I HIGHLY doubt your amp is shoving 2w per channel! The pb2 I own can but only with the correct Buffers and when it's on high gain.
Either way I know the feeling, and rest assuared that I doubt your amp can push the d2k to it's 2000 mW or 2W max