Featuring a 6n4 preamp section and two 6p6p power tubes in a dual Class-A configuration, this APPJ audio tube headphone amp offers high resolution, sweeping soundstage presentation, and full tonal quality. Compact and elegant, with solid housing, the amplifier is designed to drive high-impedance headphones all the way up to 600 ohms with little clipping or distortion. It also features audio-in and audio-out functions through the RCA ports.