This is the schematic diagram of 400Watt stereo power amplifier which use power transistor to work.

This amplifier in addition to providing good sound power, also with excellent quality and a high fidelity with low noise, to obtain the 400 watts we can put 2 speakers of 4 Ohms or 4 of 8 Ohms. The circuit require symmetrical power supply.

400Watt Stereo Power Amplifier Part List

Transistors:

D1047 – 4 pieces

B817E – 4 pieces

A1015 – 6 pieces

TIP41C – 4 pieces

TIP42C – 4 pieces

Resistors:

6.8 ohms – 1W (blue, gray, gold) – 4 pieces

100 ohms – 1W (brown, black, brown) – 4 pieces

18K – 1 / 2W (brown, gray, orange) – 4 pieces

1K – 1 / 2W (black brown, red) – 2 pieces

10 ohms – 1W (brown, black, black) – 4 pieces

270 ohms – 1 / 2W (red, violet, brown) – 2 pieces

10K – 1 / 2W (brown, black, orange) – 2 pieces

330 ohms – 1 / 2W (orange, orange, brown) – 2 pieces

56 ohms – 1 / 2W (green, black) – 2 pieces

27 ohms – 1W (red, violet, black) – 2 pieces

820 ohms – 1 / 2W (gray, red, brown) – 2 pieces

0.47 ohms – 5W – 8 pieces

Capacitors:

0.1uF/100v – 4 pieces

47uF/63v – 2 pieces

2.2uF/100v – 2 pieces

330pF (ceramic) – 2 pieces

4700uF/63v – 2 pieces

Miscellaneous:

Diode 1N4004 – 10 pieces

Diode P600J – 4 pieces

2 coils of 10 turns with 1/4 copper core 18.

7 amp 33x33v transformer – 2 pieces

Power Supply Schematic for 400Watt Stereo Power Amplifier

The power supply circuit is simple, you may use 10A transformer and 6800uf of capacitor. The diode value refer to the current value from transformer and it should be have higher value. For example if you use 7A transformer, then use 10A diodes.