BMK2 used in cathode-biased amp

[Champ81]

I completely understand what you said about the voltage rating of the cap. I meant to add that it's about saving the space. So a lower voltage means you can go higher in capacitance since size will free up the space. Higher voltage ratings in this situation would be a waste of real estate.

Everytime I bias I do set the idle bias at idle with the MV at zero. It was only that I injected signal and monitored after setting the idle at zero master volume I saw the current fluctuations and was a bit freaked out to see some high readings. I'm I'm rest assured now.

For the amp in question has 2XEL84's. That is the one I set to about 27mV of idle current at MV zero. Va (Measured at pin 7 of power tubes) is 347.8V. At first power filter cap is 355V. I was always not sure what is Va. Sorry for the dumb question. I always saw it as V (anode) so the anode (plate) of the power tube.