(...) And, just repeating Morrison, some recipes almost 20 years old are not enough, specially considering the much higher extreme quality we can get now from stereo systems.
Why would you think that? Good Engineering Practice is always good engineering practice. More than a few of the high end audiophile practice don't come close to following 'Good Engineering Practice's'.
Now that balanced analog interconnects (although hi-fi products often do them incorrectly) and digital interconnects are becoming popular the magnitude of power system problems as been reduced.
Yes, Good Engineering Practice is always good engineering practice. But sometimes we need more than just that. Your statement that Now that balanced analog interconnects and digital interconnects are becoming popular the magnitude of the power problems have been reduced just shows the danger of excessive Good Engineer Practice. Some of the best systems I have listened to were single ended systems. Many good engineers refer that domestic audio systems do not need balanced analog interconnects because the distances are too short and the systems have low complexity.
Please do not consider that I am endorsing that Poor Engineering Practice is needed for good sound quality. I am just considering that very often practical life needs compromises.
I can not forget that the people who follow mainly Good Engineering Practice have concluded and proved long ago that we should forget about stereo and migrate to multichannel.