This circuit was obtained from a Philips documentation from 1968. The transistors can be replaced with equivalents, only with care so that the doubles are exchanged for matched pairs.
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...