Simple power amplifier 2N3055 style popular in the 70's. Many similar designs on the web.
70W in 8 ohms with a 60V single supply. Sensitivity 800mV.
T1: NPN : BC547C
T2: PNP : BC557C
T3 : NPN : BD139
T4 : PNP : BD140
T5 and T6 : 2N3055 (or better with 2SC5200)
Diodes : 1N4007 on the same radiator with T5 & T6.
Adjust the 30 ohms resistor (100 ohms adjustable should be used) for a quiescent current of 40mA in the 0.2 ohm resistor with shorted input).
