hi Elso,
>> Gromanesque
Don't get the meaning of this word. Pls explain it in a simple words
>>What about two footballplayers kicking the ball back and forward between each other?!
This is a right metaphor for class AB otput stage, not A.
>>But as I see it you get twice the drive to the outputstage with a complementary inputstage
It's a total different stories about input and output complimetary stages. For input, you do not have to achive perfect symmetry for AC collector currents of Q1 and Q8. This currents just get summed at out1 point. As the first level of approximation, Q1 and Q8 are independent amplifiers. You can even substitute either Q1 or Q8 with constant current source and just loose 6db gain. Imbalance between Q1 and Q8 AC currents does not affect on linearity of the amp.
For output stage, you HAVE to get perfectly the same devices.
But they doesn't exist. So you get some errors at output stage.
Another well-known fact is compensation of even harmonics at push-pull stage. This leads to "comb filtering" effect that human hearing do not like.
For this reasons, i choose SE output stage.