lol I think you're on to something and anyone who has one of these amps and won't give pictures of the inards of this amp is trolling and of no help to the hobby.no contradiction...it's a class AB-1 preamp...LOL
On this note a bunch of wirewound resistors and tantalum caps used as biasing will not give you AB biasing or rather will not stay in AB for milliseconds and will move futher away from AB the longer the biasing is engaged.
No regulation is the cause for this issue, this would be possible if one had a circuit that controlled the output of the voltage reduction circuit to the base of the output transistors and this my friends constitutes more than the twisting of resistors and cap leads.