This circuit works as both an injector and a signal follower. We found it in the May 1994 issue of Electronics Now. The Z1 headphone must be high impedance.
This circuit is from an old documentation but still current for assembly. Just use BC548 instead...
Rumble is a low frequency noise between 25 and 200 Hz that appears in old turntables, affecting...
This circuit is from an American 1964 documentation. Transistors of the time are used, but modern...