Details：

Based on the famous JC-2 amplifier circuit.

Fully symmetrical FET input, voltage level reaches 20MA-25MA class A output.

Because it is a fully flat symmetrical structure, the midpoint is very stable and no input and output capacitors are required.

Using parallel power supply, the characteristics are close to the battery, pure, low internal resistance, natural listening.

Input stage : 2.5-3MA

Voltage amplifier stage : 20-25 MA

Work voltage：AC15V-0-AC15V above 20W

Gain: 5 Times

Pcb size: 115mm x 94mm

Debug instructions:

1 Adjust the fine-tuning resistor 2K of the power supply part to make the power supply voltage stabilized output +——15V--20

2 Adjust the 1K trimmer resistor so that the voltage on the 1.5K resistor is 2.5--3V (do not exceed 3V, the midpoint and heat generation are relatively high, there are labels on the board

3 Adjust the 500 ohm trimmer resistor to make the output voltage close to 0MV

Package included：

JC-2 preamplifier pcb x1 （Not included any parts ）

Assembled board ，just for reference：