Repairing Bogen - PSU missing resistor

[Toddebner]

I'm working on fixing a Bogen mx30a tube amp and after tracing the scematic (working on putting on the pc, then will share) found that there appears to be a missing resistor after the B+ Voltage.

i.e. the transformer secondary feeds the diodes which then feed a filter / resistor network.

The voltage to the centertap of the output transformer comes first, then there is a 1.5k resistor leading to the next filter cap and to the plates of the output tubes (7868's).

Then there is no resistor leading to the next filter cap. However the next filter cap leads to the plates of the preamp stage.

So the question is "How do I determine what resistor value should go here?".

I am a newbie to this but have learned that I can use ohms law to figure this out. However, I'm not sure how to calculate given this is a complex circuit with multiple resistors, caps and tubes in the circuit.

Can someone point me to a good psu design guide that shows how to determine the resistor values in the voltage / resistor divider network ?

Thanks