This 1965 Philips circuit uses old company transistors like the BFY51 and BFY50. The circuit is powered by 12 V and the power gain is 8.9 dB.
This circuit was found in a Popular Electronics from the 90s. Transistors are general purpose...
This circuit works with only 1.5 V and can be powered by a solar panel. The circuit is from 1991....
This circuit has a maximum output current of 5 A, and the 2N3055 must have an excellent heat sink....