Here is a conventional power supply for tubed equipment. The secondary voltage secondary current can be between 80 and 300 mA depending on the application. This diagram was obtained from an early documentation from the 1960s.
Critical components in addition to the tube are the transformer and the filter shock. These components can even be obtained from outdated old equipment such as amplifiers, radios and televisions from the 50s and 60s.
The filter capacitors must be high voltage and the values may be close to those indicated. The 6.3 V winding is for the filaments of the valves of the fed circuit.
In figure 1 we have the complete diagram of the power source. See more in the article Sources for Tube Equipment on this site.
Figure 1 - Complete diagram of the power supply.
