Included tubes: 1 pair of 6AS7, 1 pair of 6SN7, and 1 274B * Tubes shown on the pictures are not included. * AC power supply cord, interconnection cable are not included Features Point-to-Point wiring True balanced topology All tubes. No semi-conductors in the entire circuitry One 5AR4 rectifier tube. Direct substitute: 5U4G Two 6SN7 drive tubes Two 6AS7 / 6080 power tubes Smooth balanced attenuator One balanced XLR input One single-ended RCA input Two 3-pin balanced headphone output (left and right ch) One 4-pin balanced headphone output One single-ended headphone output High and low impedance switch Specifications Headphones impedance : 8—600 Ohms Input impedance: 100 Kilo-Ohms Frequency response: 8 Hz — 50 kHz, -3dB Output: 1500mw @32 ohms, 700mw @600 ohms Signal/Noise: 92 dB THD: