Because the 2N3055 transistor is an disassembled tube, it looks a bit old.
The 2N3055 transistor is ST now,not Motorola.But it does not affect the quality of the product and it can
be used normally.
The finished board is an assembled, adjusted and tested amplifier boards of the classic JLH (John-LinseY Hood)
1969 class A amplifier. While JLH 1969 is a simple design, it is still one of the best transistor amplifier.
1. The circuit board adopts JLH1969 classic circuit design, and the PCB board adopts double-sided gold
plating process, which is sturdy and durable.
7.Application: Suitable for listening to vocals, you can choose 3-5 inch full-range speakers;
you can choose 5-8 inch full-rangespeakers for listening to bass, or you can choose 2 way speaker with
power below 120 watts, 8 inches or less, and true sensitivity above 86.
Tune midpoint: universal table hit voltage profile, black pen then the red pen then GND TP1 test holes
(TP1 at the output capacitor positive) board, the adjustable resistance KT1 it is 1/2 of the supply voltage.
Modulated current: 10A universal table hit stalls, a pen then positive power supply, the other one pen then
VCC terminal, adjust the adjustable resistance KT2 change the current board size.