This excellent amplifier with complementary symmetry output stage was taken from one of my audio books. It provides an output of 5 Wrms in a load of 8 Ω and must be powered by in 18 V supply with at least 600 mA per channel. The output transistors must be provided with heat radiators and the source must have excellent filtration. The printed board must have thick tracks for the most intense current lines. The audio input cable should be shielded. The circuit needs at least a 500 mV signal to be excited to full power.
