Make cheap speakers using waste circuit boards (TDA1013)

The author bought three TDA1013B integrated blocks at the price of three yuan, and made an ultra-low-cost speaker with waste circuit boards and disassembled parts.

TDA1013B is often used in the sound system of large-screen color TV. It has a DC volume control circuit that changes according to a logarithmic curve. The power supply voltage is 10V~30V. It has independent preamplification and power amplifier. The power supply voltage is 14V, the load is 8Ω, and the output power is 10W. By changing the voltage of pin 7 (0V~5V), the volume can be adjusted without sliding noise.

Find a suitable scrap board, remove all parts, install three integrated circuits according to the circuit in Figure 1, solder the resistors and capacitors at the corresponding positions around them, and carefully add flying wires or cut the copper foil connection. The dual op amp (NE5532) in the heavy bass circuit requires positive and negative power supplies. You can take a transformer with a height of no more than 4cm from a scrap mobile phone charger and form a positive and negative power supply according to the circuit in Figure 3. The power amplifier power supply is modified with an electronic ballast as shown in Figure 4. Remove the original choke coil, the primary coil remains unchanged, and the secondary is wound with Φ0.31mm enameled wire for 18 turns, with a center tap. The diode in the figure must use a fast recovery diode. Figure 2 is a dual-input switching circuit, J is a dual-channel small 12v relay, and the shell is modified from a car radio.