This circuit was found in an article in Radio Electronics magazine from May 1975. The circuit has several features and is powered by a 12 V source or battery.
This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time....
This old oscillator using germanium transistors has a high impedance headphone as inductor to...
This preamp with several inputs using germanium transistors from the time was found in Japanese...