This 6-tube two-channel amplifier was found in an American documentation from 1947. The circuit is two-channel with a separation of bass and treble.
The power of this converter is not the greatest, it can only supply small fluorescent lamps,...
This circuit is in the very datasheet of Texas Instruments that manufactures the component...
Found in a PE Hobbyst Handbook from 1991, this circuit uses a common photocell as a sensor. The...