Well first of all I do thank you all for the attempts to help.
I do have half knowledge or less when it comes to electronics.
I can follow the explanations why some things work the way they do but if then they do not work properly it requires an altogether different level of knowledge to know where to tweak it.
The amplifier I mentioned here simply blew the fuse and the two output transistors when I switched it on. I have 5 working ones, this one does not work.
Obviously I am reluctant to simply put two new transistors in and switch it on again. I am trying to figure out why it did this and the safest way would be two build it in stages and 'inch' towards the complete amp. Nigel strongly argues that that is not possible, others are less strict and suggest testing stages here and there.
As I said I am in no position to argue either case, all I hope is to learn something here and in the process -hopefully- also finish this amplifier without having to buy output transistors by the caseload.
And now I wonder which advice I should follow, test the whole thing as one or try some partial solutions?!?!