This common circuit is from September 1984 Radio Electronics. The transistors are general purpose, and the frequency is given by the capacitors.
Found in American documentation from 1968 this circuit is based on discrete components in addition...
This preamplifier with RIAA equalization was obtained in a documentation from the 1980s. The...
This oscillator with the PLL 4046B was obtained from a 90s Radio Electronics. The circuit...