Description:A valve amplifier or tube amplifier is a type of electronic amplifier that uses vacuum tubes to increase the amplitude or power of a signal.Connect this 6J1 tube pre-amplifier between sound source and and it can effectivelyfilter digital flavor. Tube amplifierproducesa warmeror morenaturalvalve sound, make music and human voice is relatively good. Features:Connect the 6J1 tube pre-amp between sound source and amplifier, it will effectively filter digital flavor, the music and human voice will be relatively good.Eight 470UF capacitor filter is very clean, excellent power system lead to no hum, filaments are powered with DC 12V and need to be connected in series in order to reduce noise.Coupling capacitor is electrodeless electrolytic capacitor with high frequency and low resistance.Using DC 5.5*2.1 socket and AC 12V transformer, you can also use AC 12V transformer without plug, just need to weld the power cord onto the circuit board.This kit comes in parts so you can assemble them together by yourself, enjoy the process of building your own tube amplifier.Specifications:Type: 6J1 tube (substitution model 6AK5, 6AU6, 5654 etc.)Channel Types: 2.0 / stereoVoltage & Current: AC12V 0.8A or abovePower Interface: 5.5 * 2.5 plugCircuit Board Size: 77 x 75mm / 3.03 x 2.95"Instruction: 1, AC 12V Input: using DC 5.5*2.1 socket and AC 12V transformer, you can also use AC 12V transformer without plug, just need to weld the power cord onto the circuit board. DC power input can not be used, or it will not work.2, Sound Channel Input: Connected to mobile phone, computer, MP3, MP4 and many other music players.3, Sound Channel Output: Connected to the audio signal input of power amplifier.4, Power Switch/Volume Knob: Rotate the knob anticlockwise to turn down volume, and continue rotating until you hear the sound "tick" to power off. Rotate the knob clockwise until you hear the sound "tick" to power on and continue rotating to turn up volume.Package Includes:1 x PCB Board1 x 2W 2.2 Metal Film Resistor6 x 1N4007 Large Current Diodes6 x 4.7K Resistors2 x 1K Resistors4 x 47 Resistors2 x 2.2K Resistors2 x 470K Resistors2 x 100K Resistors2 x 200 Resistors9 x 50V 470UF Capacitors4 x 50V 1UF Monolithic Ceramic Capacitors2 x D667 Transistors2 x B647 Transistors1 x 50K Potentiometer2 x 3mm Blue LED1 x DC005 Power Connector2 x Tube Base2 x 6J1 Tubes2 x RCA Base1 set x Standoff and Screws1 x Potentiometer Cap.