With a 22 V symmetrical power supply this amplifier provides 15 W of output power with excellent sound quality. The circuit was found in a 1991 documentation being made some modifications to use more current components. The LEDs are stabilizers of any kind and bipolar transistor can be BC548. The operational amplifier for better sound quality should be high speed. The output transistors admit equivalent and should be provided with good heat radiators. R5 adjusts the symmetry of the output signal. The source must provide at least 3 A and the input impedance is high.