This Public Address amplifier was found in a 1947 amplifier manual. The power supply uses two transformers with two rectifier tubes.
This circuit was found in an old Electronic Design. It makes use of sidacs and operational not very...
Although it was found in a British magazine 1976, this circuit can be easily upgraded with the...
This circuit that uses only transistors that are still common was found in a 1995 documentation. The TIP41...