This 20 W amplifier from 1944 used triode tubes on the output which was not an improvement solution, but served the Public Address applications of the time which were of lower fidelity. The circuit was powered by the power grid.

This 20 W amplifier from 1944 used triode tubes on the output which was not an improvement solution, but served the Public Address applications of the time which were of lower fidelity. The circuit was powered by the power grid.