Powerful dynamic and sweet TUBE sound; With Electro Harmonic 6922 TUBE; 3 Band graphic equalizer; Hardware Passive EQ (No op amp IC); Cute and beautiful looking; Pure Class A Tube amp No op amp IC; Low voltage good safety; Powerful for any headphones; Input Impedance:100KOhm; Output Impedance: 20~600 Ohm; Gain: 30dB; Frequency response:10Hz~60KHz +/- 0.25dB; Signal/Noise Ratio: >90dB; Dynamic range: 84.6dBA(300 ohm) 89.8dBA(33 ohm); THD: 0.016%(300 ohm) 0.45%(33 ohm)I; MD + Noise: 0.045(300 ohm) 0.42(33ohm); Dimension: 79mm (D) x 130mm (W) x 44mm (H); Input: 1 x Stereo RCA 1 x Stereo 3.5mm; Output: 1 x Stereo 6.35mm