[Tubejunke]

With capacitors you can use ANY higher voltage than what the schematic calls for. Never go by the old part because somebody might have subbed in whatever they had laying around; always check the schematic. As far as the value of capacitance goes, you always go higher; never lower. I believe the percentages listed in other posts on this thread about cover it. Last, always observe polarity with electrolytics or you will likely have fireworks and ruined parts. Polarity is not an issue with other types.