This simple, unregulated power supply with an approximate 6 V output voltage can supply currents up to about 500 mA depending on the transformer. The diodes can be 1N4002.
We found this circuit in a 1985 technical publication. The circuit uses PUTs to drive lamps....
This high-powered megaphone circuit is from a Radio Electronics from December 1964. Note the use...
This amplifier with differential input uses two old op amps but can be implemented with modern op amps....