I have always gotten very enjoyable sound out of my X2's with 2 amps: Cavalli Liquid Carbon (v2): sure, it's a warm amp. sure, it shouldn't work with X2's--but it does. it really does... Lake People G109-A: another slightly warm amp, more power than the LC (not that it matters w/the X2s)--it gives them a very even, impactful, musical sound. The X2s definitely can scale up, sound somewhat different/better on different amps. Then again, the 1st source I used mine with (FiiO 10K DAC/amp) was tiny & cheap, and still sounded excellent...because the X2s just about always sound good.