This circuit of the 70's uses transistors of the time. The circuit can amplify signals from 10 Hz to 100 kHz and modern equivalent components can be used. The circuit is from Ferranti.
This circuit is one of many that the reader can find in this section for testing crystals. The...
I found this circuit on a December 1976 Radio Elettronica. The Italian magazine no longer exists, but...
June 2017 - Mouser Electronics has in stock the new AC Metallized Polypropylene Film Capacitors...