400 watts Stereo Amplifier using STK4050

This 400 watts stereo amplifier circuit is made based on the Sanyo STK4050 hybrid integrated circuit, a high quality low noise amplifier. Its maximum output power is 200W per channel. To achieve a 400 watts stereo amplifier, two such integrated circuits are needed.

It is very important that both amplifiers use a large heatsink due to the great heat that is generated. As you can see from the diagram, it is only necessary to place the additional components to the integrated circuit to make it work. The speakers used are 8 ohms.

Unregulated Power Supply for the 400W Stereo Amplifier

As a power supply, two unregulated sources are used, such as the one in the diagram. Two 120/240 VAC to 60VAC, 2.5 to 3 amps transformers are used. Transformers must have a central tap (-30V – 0 – 30V).

With these transformers, +/- 42 VDC unregulated voltages are achieved. (-Vcc and Vcc).

This type of circuit can be used to build high-power compact portable amplifiers.