you should be able to use the m50x without an amp. it should pair well with most of the portable devices. usually better amp/dac should give you better results, but still it's all depends on your current source quality, as an example if you can hear some noice or can't get any listenable volome, then you might need a different amp/dac. end of the day it doesn't matter how good is your headphone, amp, dac as long as you listening to low-quality audio. it's garbage in -> garbage out.... for now I suggest you first just use the m50x without any amp/dac.