In article , Uwe
writes:

I am looking for info regarding a simple power supply with a full wave
rectifier (I got a 6X5).
Mainly I need to know the 'to be expected output voltage' (capacitor
filter)for any input. I don't have info on that.
Do the formulas for solid state rectifiers apply??

Not quite. The voltage drop across vacuum diodes is
considerably higher and varies with different rectifier diodes,
typically 40 to as much as 100 Volts. You can find some
representative curves of DC output voltages versus AC input
for capacitor-input circuits in older texts of 40 to 50 years
ago. Some old vacuum tube data manuals give 'typical'
voltage drop values.

You can get an approximation for the peak DC output by
taking 1.4 times the AC RMS input, subtracting about 50
volts from that to begin a rectifier circuit for a 50 to 100 mA
HV supply. From there on you can pin down more exact
values with rectifier tube data.

A slight advantage of vacuum tubes in capacitor-input rectifier
circuits was that the very high initial turn-on surge isn't there;
a vacuum tube diode literally turns on slowly as the filament
warms up. In cheaper tube designs that was offset by the
higher heat dissipation of tube rectifiers creating a local hot
spot much higher than with semiconductor rectifier diodes.
[typical heat dissipation of a 5Y3 common dual-diode in 100
Watt units was 15 to 20 Watts all by itself]

Len Anderson
retired (from regular hours) electronic engineer person