We found this circuit in a Radio Electronics from the 90s. Transistors admit current equivalents, especially the power one that is not a common type today.
This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time....
This traditional crystal radio circuit, but which has a modern version with diode, was found in an...
This headphone amplifier using a pickup coil can be used as an extension for devices such as TVs,...