This circuit was obtained from a Radio Electronics from the 90's. The circuit limits the strength of an audio signal preventing saturation. Equivalent operational amplifiers can be tried.
In the 70s, Ibrape launched an excellent audio pre-amplifier kit to be used in amplifiers of the...
This amplifier stage was found in a 1956 Sylvania manual and has an unusual configuration with a...
Found in a QST magazine from the 90s, this powerful unit is intended to supply a VHF transceiver for...