The amplifier used in the telephone circuit is based on the KT3102E. Tested in operation.
In a book about telephones, I saw a circuit diagram for an amplifier using a KT3102E transistor. I soldered it together. Connected it. Listening.
In a book about telephones, I saw a circuit diagram for an amplifier using a KT3102E transistor. I soldered it together. Connected it. Listening.