This symmetrical power supply uses two old filament transformers. The circuit was obtained in a documentation from the 80's and the diodes can be 1N4002.
Found in a Popular Electronics this circuit has double regulation. The integrated circuits used...
Any operational amplifier, like the 741, can be used on this oscillator whose frequency depends on R1...
This integrated amplifier was found in an English magazine that no longer exists, from 1975. The...