We found this circuit in a 1980s publication on telephony. The circuit uses an integrated amplifier from that time, which is uncommon today.
This is one of the channels of an amplifier suggested by Westinghouse in 1970s documentation. The circuit...
The basis of this circuit is a double T in the feedback, which has the components calculated to...
This circuit was obtained from American documentation from the 1990s. The transformer can be a car...