OK since I have found my self messing with older gear I have noticed that some of the caps you may not find that value anymore expecially in the high voltage ranges used in tubes. SO How far off can you be and still be close enough. I plan on replaceing the caps in this Bogen MX 60 PA head as I go along. first caps that will be replaced will be the 40 mfd 300 VDC caps that are coming off the rectifers. OK that one is not bad it is a common cap and I suspect I will just use instead of the cardboard can type that is in there some plastic covered aluminum ones that have the leads out both sides as I can get them from my tech friend. However one can a 4x multi is 20 20 mfd /450 vdc 10 10 mfd /350 vdc in my amp which on the schematic is 20 20 20 20 mfd with the first two again 450 and the last two 350 and the schematic said that some amps may have either configuration. So I would suspect the 20x4 would be easier to find. Same with a 5 5 5 5 Mf with the Voltage rated at 200 vdc can in this amp I would suspect that might not be easy to find so I might have to go with a higher value MF can so what can ya get by with and I suppose higher is better in both MF and Volts.