This circuit was found in a 90s Popular Electronics. The integrated circuit used is uncommon today. The power is about of 2 W.
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...