Oh, well that's a problem then. Funny, the first version of this actually used a precision 2.5v reference with the pots for the reference signal.
Since the supply is 12v on the money and wouldn't have any headroom for a 12v reg, could I use a 9v battery or 7809 to power the opamp and provide reference voltage to the pots? The only problem I can see with a battery is if I go back to a big power module, they need a good bit of drive current. More than a 9v could supply for too long.
Everything runs to the star ground except the fan and the power led. The 510ohm resistor literally ties directly to star gnd and pin3.