This commercial signal follower was found in a 1967 Japanese magazine. It uses germanium transistors and provides a speaker output without the need for a transformer.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...