This circuit is from a 1980's documentation for telecommunications. The circuit is used in SSB and the diodes must be suitable types for the application. The audio input is low impedance.
In the figure we have a simple amplifier stage with a temperature compensated general purpose...
This good power amplifier was found in a Japanese magazine from the 1970s. The circuit uses...
This circuit was found in an article in Radio Electronics magazine from May 1975. The circuit has...