3-tube receiver 2 (T1603E)

Using known tubes, this receiver was found in a Radio Electronics from 1949. The circuit does not include the power supply.

High Power Alarm (CB26223E)
This circuit was found in volume 5 of the 1995 Encyclopedia of Electronic Circuits. The circuit is based...
9V Recorder Switch (CB23652E)
This control circuit was found in a Radio Electronics from May 1965. The circuit switches a...
8W Amplifier Using the TDA2040 (CB443)
The TDA2040 is not a common IC these days, but if you find one you can build this high quality...