This circuit appears in several versions in publications of the time and can be modified by changing the capacitors. This one is from Radio Electonics magazine from October 1992.
This configuration appears elsewhere on this site. We obtained it from a 90s Radio Electronics, based...
This circuit is from a Fairchild digital clock module shown in the March 1977 issue of Radio...
This good power amplifier, a few tens of watts, is part of an article in the December 1972 Radio...