Hybrid vacuum tube amplifier kit "cuBic kit% Daburuku~ote% TU-H82 Hybrid of vacuum tube input buffer + D-class speaker amp (AB-class headphone amp built-in) DC-controlled electronic volume built-in the amplifier IC. Therefore the volume deflection between right and left channels at small sound volume is minimized. Headphone output Built-in USB-DAC for PC connection Interlocking the amp power ON/OFF with the PC USB power selectable