The Fiio E9 is a stellar value for its price! This amp can drive the heavy 300 Ohms (HD600, HD650) or even the 600 OHms (DT880) headphones to deafening levels...not that I encourage that kind of thing! But there is more going on here than raw power. This amp sounds great! It has a slightly warm sound, with tight bass and great mids that don't obscure the treble. You can also pair this with the Fiio E7 DAC and get great sound from your computer, too! I normally use it with the Fiio E9 line out from Ipod Classic. A better value in headfi cannot be found!