In summary, yeah. I would gladly spend 500€ or 1000€ on a good class A/B amplifier afterwards. Something without surprises. But the situation is hairy. This guy doesn't want to back down. He's insistent on his abilities which I don't care for anymore. Looking closely at the innards of the amplifier, his soldering is sloppy. Some tin was floating around in the casing. And I was driving as gently as possible with the anxiety that vibrations and bumps would desoldure components.
The artisan has a well equipped workshop and a great listening room. He has everything to succeed. That's why I stuck around for so long. I doubt that I'll ever get my money back. I don't want to deal with him anymore. The anxiety and amount of hours spent on driving is a burden on my life. But he'll be back next Sunday.
Presently, the amplifier displays an audible "100 Hz hum". There was hiss prior to that, it is now resolved.
Yeah the situation sucks but I'm in good health and my financials have never been better. I can afford to lose some cash (just not every month during the year like that). Heck! If only we lived in a world where we could mass produce good amplifiers for a few hundred bucks LOL