We found this tube receiver in a 1950s Japanese publication. The circuit uses 5 tubes and has an RF amplifier stage for greater sensitivity. The power supply is not shown on the circuit.
This LED special effects circuit was found in the February 1992 Radio Electronics magazine. The...
Found in an American publication from the 1980s, this circuit can be found in commercial sound...
Found in Philips' 90s documentation, this small source can use modern transistors like the BD135...