... , 2x18W 3, Frequency: 18Hz-50KHz 4, Warranty: 3 years Stereo Integrated With headphone amplifier HI-218 FEAUTUREHI-140 tube amplifier have ... Distortion<0.4%VoltageAC110V/220V 60Hz/50HzDimension430x400x330mmGross Weight20kg Naphon : Stereo Integrated With headphone amplifier HI-218