This is a warm sounding amp and really smooth with enough power to drive 2 headphones simultaneously. As Lan647 was saying that it could drive 2 high end headphones without a problem, I can drive my beyerdynamic t1 & the sennheiser hd800 with ease at the same time. Pretty neat feature if you wan't to compare 2 headphones.   I've compared these with the nuforce icon hdp and it pretty much beats it at every aspect except the nuforce's extra ports and compatibility.   Headphones I tried them with: Sennheiser HD650, HD8000, Beyerdynamic T1  ...