Two simple but powerful stereo amplifier circuit that beginners and hobbyist in electronics can try

Attack EX1200 – Stereo amplifier

Used transistors: XBF422, BD139, BD140, TIP31C, (2SC328 & 2SA1302) Output pair, (+58V, -58V Dual power supply)

One channel circuit shown.  The other channel is similar.

Attack MA3000 Stereo amplifier

Used transistors: 2SA1145, 2SC27055, 2SA1321, 2SC3334, 2SC4793, BD140, BD139, 2SA1837, (2SC5198 – 2SA1941 Output pair – 6 numbers/channel), LM339IC-signal indicator LED drive