Introduction:

The circuit refers to the well-known JC-2 circuit design, fully symmetrical FET input, voltage level up to 20mA-25mA Class A output, mellow and durable, delicate, crystal clear, well-balanced, very close to the style of a tube amplifier, and very cost-effective , Because it is a fully flat symmetrical structure, the midpoint is very stable and does not require input and output capacitors. The power supply part adopts a class A parallel connection, and the music is very dynamic.

 

Parameter:

Input voltage: AC 15V--0--15V

Amplifier type: Class A

Input stage: 2mA

Voltage amplifier stage: 20-25MA

Gain: 5 Times

PCB Size: 115mm * 93mm

 

NOTE: This is a Bare PCB, and all parts need to be matched by yourself.

Debugging instructions:
1: Measure the GND voltage between A and B, and adjust the 2K (202) adjustable resistor voltage to DC+/-15V.

2: Measure the voltage at both ends of the 1.5K resistor, and adjust the 2K (202) adjustable resistor voltage to 2.5-3V.

3: Measure the output midpoint voltage and adjust the 500R (501) adjustable resistor to make the voltage close to 0mV.