3-tube Amplifier (T691E)

This circuit of only 3 tubes has power of a few watts. Found in a publication from 1943. Power supply with transformer and double diode is included.

Fadder (CB4750E)
This effects circuit can be used with microphones or guitars. The circuit is from an American...
Resolution enhancement circuit for bridges (CB25895E)
This circuit allows you to modify the resolution of a measurement bridge. It was found in the...
High Power Driver (CB6651E)
This high-power circuit from a Popular Electronics of the 80's makes use of common SCRs that admit...