Here is a simple project of a 6W+6W stereo amplifier using a 14-pin LA4440 IC. This amplifier can deliver an output power of 6W on a 4-ohm speaker (6W each on the left and right channels). The amplifier operates on a 12V power supply.
Except resistors R1 and R2, all the external components used in the circuit are electrolytic capacitors. The author’s prototype is shown in Fig. 1.
Fig. 1: Author’s prototype
Circuit and working
The circuit diagram of the 6W+6W stereo amplifier is shown in Fig. 2. It is built around LA4440 (IC1), two loudspeakers (LS1 and LS2), and a few other components.
Fig. 2: Circuit diagram of the 6W+6W stereo amplifier
Pin 11 of IC1 is connected to the +12V power supply. The electrolytic capacitor C12 (1000µF/35V) is connected between +12V and ground to act as a filter.
The left speaker (LS1) is connected to pin 10 of IC1 through electrolytic capacitor C8 (220µF/35V). The right speaker (LS2) is connected to pin 12 through electrolytic capacitor C9 (220µF/25V).
A 3-pin connector (CON2) is provided for connecting the audio input signal. The left channel audio input is connected to pin 6 of IC1 through capacitor C1 (4.7µF/35V), and the right channel input is connected to pin 2 of IC1 through capacitor C2 (4.7µF/35V).
Construction and testing
You can assemble the circuit on a 5cm×7cm veroboard or on a PCB whose actual-size layout is shown in Fig. 3 and the components layout in Fig. 4.
Fig. 3: PCB layout of the stereo amplifier Fig. 4: Components layout of the PCB
Download PCB and Component Layout PDFs: click here
First, collect all the components like electrolytic capacitors, resistors, IC LA4440, 3-pin connectors, wires, etc. Then, take a 25-watt soldering iron and solder all the components, as shown in the circuit diagram. Solder a 3-pin connector on the PCB/veroboard for audio input. The middle common terminal of this connector is to be co