This circuit can have a power output of 10 Watt. It simply uses ordinary transistors. The 10 w amplifier circuit is unstable if the input is not connected. When performing the test, connect a resistor (about 3k3).
List of Transistors:
Tr1 : BCY70 (or BC 182L or BC212L or BC214L)
Tr2/3/4 : BFY50/51
Tr5 : BFX88
Tr6/7 : 2N3055
The Power supply for 10 Watt Transistor audio amplifier requires smoothed voltage about 20 to 30 volts. Peak power of more than 10 Watt. The table shows the approximate voltage that is expected when using a 24v supply and a variable resistor is set to deliver a current of about 40mA in the output stage.
| Test point | Approximate voltage |
| Tr1(e) | 12·5 |
| Tr1(c) | 0·65 |
| Tr2(c) | 12·5 |
| Tr3(c) | 14·4 |
| Tr4(e) | 13·7 |
| Tr5(e) | 13·1 |
| Tr5(c) | 0·6 |
| Tr7(c) | 13·1 |
