Found in a 1969 Electronics World, this circuit generates low frequency signals with two repetition bands. Transistors support modern equivalents.
This circuit was found in documentation from the 70s. We can try current JFET transistors....
This is the power supply circuit for the amplifier in the previous circuit. The source is...
This bridge circuit is designed for 8-ohm speakers delivering a few watts of power. The circuit is from...