frequency response insertion loss self noise input impedance output impedance tube compliment power fuse compliment 20hz - 50khz, +/-1db none (vacuum tube makeup gain amplifier) below -75db 600 ohms capable of driving a 600 ohm load (1x) 12AX7, (1x) 12AU7 (graded for low noise/low microphonics) selectable 115v 60hz/230v 50hz via standard grounded 3 conductor IEC cable 1amp, 250 volt, fast blow input transformer balanced, pin 2/tip=positive, pin 3/ring=negative, pin 1/sleeve=ground output transformer