this circuit really works with nice sound quality. But the transistor gets hot even with no audio input and get hotter when in operation. Heatsink is recommended i use TIP41(npn) and TIP42 (pnp) as the two power transistors and 2n3094 for the first npn transistor. 1n4148 is recommended in because its a fast silicon diode for higher frequency. This is just a very simple amplifier and its very inefficient.
