This circuit was found in 80's Popular Electronics. Transistors are commonly used. The potentiometer R5 adjusts the gain.
This traditional complementary symmetry circuit provides 20 W of rms power at a load of 8 ohms...
This circuit can serve as the basis for a simple phone. The LM10 is not common today, but the...
Other operational amplifiers in the series, such as the MC34072, MC34074, MC35071, MC35072,...