Second, the installation and production

The printed circuit diagram of this circuit is shown in Figure 3. It includes a two-way OCL power amplifier circuit and a DC power supply circuit. A heat sink is required between the body of the 4 high power tube 2N3055 and the printed circuit board, and is fixed by screws. The resistors are installed horizontally. The capacitors and triodes are installed vertically and close to the circuit board. The soldering requirements are firm and reliable. There are two jumpers on the circuit board, which can be soldered with iron wires.

Third, debugging

The power transformer used in this circuit needs to be prepared by itself. It adopts a center-tapped dual output transformer (AC: 1 5VX2), the power is not less than 40W, and is connected to the AC~ and the upper part of the printed circuit board. After being energized, it is generated at both ends of C9 and C10. With a DC voltage of ±18V, the voltage across the speaker is zero volts.

First adjust the current of the differential amplifiers vt l, vt2, in order to avoid the large current flowing through the power tube, first short the base of vt4, vt5 with a wire, so that vt4 ~ vt7 cut off. Then solder one end of the resistor r6 to the ground and solder it to ground. The total emitter current of the differential amplifier stage is determined by r4. The R4 is adjusted so that the total emitter current of vt 1 and vt2 is 1 mA. After the resistor r6 is restored, the voltage across the speaker should be o. If there is an offset, adjust r3.

Package Included:
1 x OCL Amplifier Board DIY Kit