This amplifier, whose mounting on a printed circuit board was described in Radio Electronics of October 1960, has 35 W of power. The power supply uses a transformer and a set of 5 tubes.
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...