c1 c2 c3 c4 c5 caps ( KAT 6550 )

[bob orbell]

I don't' think 450v will be a problem for C5 because the HT arrives after the valve heaters, so the 6550's will conduct lowering the HT voltage. Bob

[John Caswell]

Careful here, as the 6550 uses 5U4 valves which are direct heated so warm up very quickly long before the 6550 valves do, so you will have full HT applied until the 6550 warm up and this could exceed the 450V rating of the capacitor. Theoretically the HT at 5U4 warm up could be 425V x 1.414 = 600V Practically it doesn't get the high and as you have the potential divider of R5/R6AB which are 5K6 and 44K, C5 could get 528V. I know I am being a bit pedantic but I think a 450V rating C is a bit low.

John

[mosschops]

Many thanks all. should be able to get 600v only going to change as it is old
Regards Steve