distortion gone

 

Since the output power is more than before then the currents from the driver transistors also must be higher, and the currents from their drivers must also be higher.

 

The very high currents cause high voltage losses and heat. Modern high power amplifiers use Sziklai Pairs at the outputs instead of lossy darlingtons:

 

Again, I disagree. Sziklai pairs have a tendency to oscillate. Darlingtons tend to be more stable. On a 55V supply the difference is less than 0.1dB. The common emitter configuration of the output transistor makes it slow to turn off, so that cross conduction is more likely than with a Darlington.

 

Again, I disagree. Sziklai pairs have a tendency to oscillate.

Curse those right-half planes.

ak

 

The +ve half clip but -ve not.
I try to decrease the Vcc (around 70-80) Because the peak is 63

 

Your positive peaks are clipped because the NPN and PNP driver transistors do not have enough hFE and do not have matched hFE. The PNP KSA1381 has a much higher range of hFE than the NPN KFC3503DS.
It doesn't matter because the difference in output level between low distortion and that clipping is very small.

 

Your positive peaks are clipped because the NPN and PNP driver transistors do not have enough hFE and do not have matched hFE. The PNP KSA1381 has a much higher range of hFE than the NPN KFC3503DS.
It doesn't matter because the difference in output level between low distortion and that clipping is very small.

Agreed. Also, there is an extra Vbe loss in the top circuit than in the bottom.
If you added a current limiter in the bottom driver (because otherwise there is only the 10Ω resistor and the transistor Hfe limiting the driver current when driven into clipping) then they would be more-or-less symmetrical - after you have dealt the @Audioguru again 's point above.