A high-End "Class A" tube headphone amplifier designed for Shangri-La Sr. headphones. Behind HiFiMan’s state-of-the-art amplifier's industrial design lies the promise of heavenly sound. It has 4 x 6SN7 dual triode vacuum tubes, a Pro Bias 580V output that can accommodate up to two other 5-pin electrostatic headphones, also features 3-pin balanced XLR and RCA inputs. The most realistic sound that reaches the highest expectations. This special amplifier performs perfectly paired with the electrostatic headphones of the same name.