Datasheet of This amplifier uses a pair of complementary transistors at the output and can provide 1 W of audio at a load of 3-ohm. Higher impedance speakers can be used. The circuit is from an English publication from 1986 and TR1 can be a | BC548. The supply can be done with voltages from 9 to 18 V. The trimpot adjusts the resting current, which must be in the order of 20 mA.
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