Good news: there is some kind of voltage divider in the preamp.. joining near the 1uF of pin 1.
Bad news: all things drawn are still there. I just don't get it
(maybe this is why it realy souns like crap?)
There are obvious signs of "modifications" all over the pcb.. and a few components seem to be missing (a resistor, diode and a capacitor, all near the power section).
I give up. I will use the datasheet tda2030 layout/pcb, since I doubt the cheap internal speaker could even tell the difference.