output decoupling caps

[jester]

Does the voltage rating matter on the decoupling DC blocking caps like say .022@600v or can it be .22 @50v?

[Sparky]

If you're referring to the caps between gain stages, yes, the voltage does matter. Since the grid of the next tube stays close to ground and the plate of the previous stage can vary from ~0V to the supply voltage for that stage, you want the cap rated for at least the supply voltage plus a safety margin - usually 400V or greater.