Hi,let's close the topic,...
I think you can ignore the regulated PS for the moment, as it should be possible to make a line stage with AC heating.
So, connect a 47k and 150k (2W) resistor in series. Put a 1000nF (electrolytic) of at least 150VDC across the 47k resistor, with the positive of the cap connected to the node between 150k and 47k. Connect the 150k loose end to B+, the 47k (and cap) to B-. Connect two 100R resistors in series across the 6,3V heater, the center of these resistors goes to the node of the 47k and 150k resistor.
Confusing description, but if you understand make a drawing and we can say if it is correct.