Using transistors at the time, this circuit was found in a 1970s documentation. Transistors support modern equivalents for 2A currents at least in the case of the output transistors.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...