[Kico]

Kiko, in most instances the 650V rule is good but in certain parts of the AF portion of the set it is possible to get a high voltage spike from static etc. thats why they advise 1000V , 1200V. It may be a rare occasion but a spike could blow the 650v cap (depending on severity could blow the 1200). There are 1000V ceramics availabe, not very expensive. PL

It was common practice with some manufacturers to use 1000 or 1200 volt rated caps in lower voltage applications because the device had less internal leakage. That's not an issue with modern caps.

Another application was across the incoming AC line. A 630 v DC cap can work there but modern rote is to use the X-Y type AC-rated capacitors.

The plate of the audio output is another location that occasionally needs more than a 630 vdc rating because of the audio spikes and AC component.

Thanks guys, I guess I'll order some of the higher rated caps just to be on the safe side.

BTW, has anyone had success in cleaning the volume pots on these. I have a small amount of "scratchiness" which I'd like to eliminate, but the pot seems pretty well sealed. If it's a risky job, I'll just leave it as is.