Small amplifier and speaker made with TDA1521

1. Power Amplifier

The high-fidelity integrated circuit TDA1521 is used. The peripheral circuit of this integrated circuit is extremely simple, and it also has protection circuits such as overheating, noise suppression, and short circuit, which is suitable for beginners to make. The front stage uses NE5532 for 10 times line amplification. The coupling capacitor can use domestic CBB capacitors or tantalum capacitors. The front stage power supply is obtained by 7815 and 7915 voltage stabilization. The power transformer should be selected above 30W. The rectifier tube can use 3A full bridge. The power amplifier circuit is shown in Figure 1, and the power supply circuit is shown in Figure 2. The circuit board can be carved with a utility knife, and the power amplifier block should be added with a large enough heat sink.

2. Speakers

1. Speaker unit: The tweeter uses a 3-inch high-frequency speaker for surround sound boxes. The woofer uses a 4.5-inch speaker for car audio.

2. Box production: It can be made of 10mm thick medium-density fiberboard, with dimensions of 270mm high, 170mm wide, and 220mm thick. The phase guide hole is designed at the back, so the speaker should be placed at a certain distance from the wall.

Connect the amplifier and speakers and give it a try. I believe that the sound produced at a cost of less than 100 yuan will not disappoint you.