The transistor on this mixer can be any general-purpose transistor. The number of entries can be changed. We found it in an old documentation. Input and output cables must be shielded.
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...