We find the original version of this circuit in an English publication (1986). It is a general-purpose amplifier for headphone or speaker of at least 65 Ω, but can be used with an output transformer for transistor radio. We changed the components to enable its assembly with current components. The power supply should be done with voltages of 6 to 12 V. For 6 V battery may be used. With power supply filtering must be good. The input impedance is high. The circuit includes a volume control. BD135 can be used at the output stage to achieve a greater power.
