Homemade germanium transistor amplifier in wooden housing.
Backside-AC input and audio input.
Backside with back panel removed.
Inside there is speaker, ciruit and transformer ...
Circuit board.
Left one is amplifier, right one is ''power supply''.
Schematic:
Measure output on testpoint v1.
To get zener value subtract 12volts from v1.
It is not necesary, to get exscactly 12volts on v2, but don't exced maximum voltage of transistor
Circuit draws 46miliamps at 12volts.
K on transistor marks means kuhler-heatsink(in german).