This circuit is from a 1977 Signetics integrated circuit manual. The output transistors can be BD136 and BD237 and the symmetrical supply can be from 6 to 12 V. The voltage gain is 10.
In this circuit, from a 1977 publication, we have the traditional version of a filter tuned to 1...
We find this circuit in an American 1980s documentation. Modern equivalent integrated circuits can be...
Found in an old Popular Electronics this circuit can also be adapted to be used as a shield. In...