This 5-tube hi-fi amplifier was found in an American publication from 1947; The output is in class B and the circuit uses a source with transformer.
Found in ancient American documentation, this circuit uses some components from the time, such as...
In the figure we have the way to compensate an operational amplifier. The circuit is valid for...
With this circuit, it is possible to excite a white LED or another type of high brightness with...