This circuit from a June 1957 Radio Electgronics is for oscilloscopes of the time with a maximum frequency of a few megahertz. The circuit is battery powered.
This circuit for controlling high power in the AC network was found in a Motorola documentation from 1968....
This amplifier is specifically designed for portable radio and recorders with a 4 ohms load....
This circuit was found in a 1973 Radio Elettronica magazine. The Italian magazine no longer...