This powerful high-fidelity amplifier was described in an article in Radio Electronics magazine in December 1973. Note the use of 8 high-power transistors that must be mounted on excellent heat sinks.
For those who like experimental circuits, here is a sequential flasher system with LEDs, which can be...
This circuit was found in an ancient American documentation. The integrated circuit is of the time...
This circuit was found in a 1977 Radio Shack documentation. The circuit is tuned to 1.4 kHz, but...