The circuit shown consists of a few watt amplifier that uses a single dual tube. This circuit can be used as the output stage of radios, intercoms and several other applications. The power supply is made with a 200 V supply (see article on sources for valves).
The output impedance of the transformer, which may be different from the indicated value.The output transformer primary has between 2k and 5k and the electrolytic capacitors have the minimum working voltages indicated in the diagram. The circuit does not include the volume control, but it can be a potentiometer of 1 M.
The supply voltage comes from external source and for the input must be used shielded cable so that the snoring does not occur. The tube is a PCL86.
This audio stage is found at the output of many TVs of the 1960s.
In figure 1 we have the complete diagram of this stage of audio amplification.
