Quote:   Thanks tdockweiler for your good answer! I've been thinking of getting the 6400's but have to do an a/b comparison with a couple of other cans. I've been reading about headphone amps here and there, and what confuses me as a beginner is the "1/8 output impedance rule/guideline"...

What amps do you KNS8400 owners use to drive them, any specific recommendations? I'm quite new to this whole world of reference headphones and headphone amps and got interested after a friend of mine blazed these cans (and their little brother, the 6400, too).