At your risk. Please take all safety precautions. A suitable safety fuse should always be connected in series with a battery in order to avoid burn injury or possibility of fire.
The resent schematic has the bias resistor from Vb to base rather than from collector to base.
Signal path: CD - Sony CD Walkman line out - Pleiades single 2N3055 - Marantz 5-C loudspeaker
When the air gapped output transformer has an impedance ratio of 64 ohms to 8 ohms the sound is good even with Vb=10V, Ic=100mA or even less.
While staying with just one 12V battery and trying to increase power output by using a transformer or lower primary inductance (less turns ratio) and increasing Ic, did not work very well. Possible cause exhausted battery or inability of the CD Walkman to drive the lowered input impedance of the single power transistor.
Changing to the MJ1000 Darlington gave a much louder sound with some distortion with a transformer of 84mH:22mH or 22mH:22mH.
Music played on CD: Sodad - Cesaria Evora, Flashdance Soundtrack
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