The Bellari HA540 MK2 is a audiophile grade headphone amplifier. The all class A signal path ensures smooth clean analog audio. The 0 feedback design means smooth natural analog response. It features 2 input paths and high gain for MP3 players, ipod, etc. and a low gain path from audio selectors, mixers, satellite receivers, etc.. It also features direct into the tube grid coupling for no loss or distortion. The unit is included with a universal power supply for use most anywhere in the world.