This little unit is everything I hoped it would be. It makes a big improvement in sound over my Fiio E7 through my Sennheiser HD558s. Since I wrote this I have moved from the 558s to the HD600 and the Aune T1 remains excellent, especially once I boosted the gain from 0 to 10 (the intermediate setting). The T1 drives these phones well with a detailed sound. The T1 allows a good introduction to tube rolling. After several choices I have settled with the Amperex 7308 a very detailed, but smooth sound.