[Ron Ramirez]

Not having access to my service info at the moment, I'd guess those 1000 volt caps connect from the plate of each output tube to ground? There has been a lot of discussion on this subject in recent years. It is generally agreed that 1000 volt caps should be used as protection against transients/spikes in the audio circuit - although I confess I have used 630 volt caps in this application and have had no problems. However, I should also point out that I don't run my sets at full volume, nor do I generally run old sets for hours on end. YMMV.