I took one out yesterday to give my multimeter a stab and of course it only has resolution down to 1nF.
However, I measures it and it says 1 nF. I measured a cap that I had laying around that is .0047uF and it reads 5 nF. So it looks like it is working. My guess is that it is actually 470pF for it to read 1nF. If it were 47pF I doubt it would register a value.
I will measure more of the caps as I have decided to do the entire board with new components while I have it apart.
Poobah, this is a 1972 Sugden amp from the UK. They started making these in the late sixties and I bet stocked up on supplies to last the few thousand produced so I am sure the caps date back to the 1960's.
What type of cap should I use to replace these? I found some wima films this size but they are rated at 1600v and since this might see 36v they are not really appropriate.
I have one more mystery (to me) component that I will take a picture of. It is a clear plastic looking deal that looks like it is either a cap or a diode of sorts.
I hope that when this is all said and down the amp works
However, I measures it and it says 1 nF. I measured a cap that I had laying around that is .0047uF and it reads 5 nF. So it looks like it is working. My guess is that it is actually 470pF for it to read 1nF. If it were 47pF I doubt it would register a value.
I will measure more of the caps as I have decided to do the entire board with new components while I have it apart.
Poobah, this is a 1972 Sugden amp from the UK. They started making these in the late sixties and I bet stocked up on supplies to last the few thousand produced so I am sure the caps date back to the 1960's.
What type of cap should I use to replace these? I found some wima films this size but they are rated at 1600v and since this might see 36v they are not really appropriate.
I have one more mystery (to me) component that I will take a picture of. It is a clear plastic looking deal that looks like it is either a cap or a diode of sorts.
I hope that when this is all said and down the amp works
For safety's sake, your caps should have the same (or greater) voltage rating as your power supply rails... This is because you never really know how things are going to "power up/down". Plus, if get a failed component; you don't want a chain reaction of failures... though sometimes there is nothing you can do.
Teflon are supposedly the best... but who has the money? If there really IS (no opinion, or facts... yet) a difference; it is small.
Polypropylene is good... "foil" instead of "metalized" is thought to be better. They are physically larger though.
I don't know what you have access to but Sprague Orange Drops (715's 716's) are good and very friendly to the wallet. These are FILM/FOIL/Polypropylene. Measure and read the specs to make sure they will fit?
Your caps are probably MYLAR (polyester... popular in that era)... they may sound fine just the way they are.
Teflon are supposedly the best... but who has the money? If there really IS (no opinion, or facts... yet) a difference; it is small.
Polypropylene is good... "foil" instead of "metalized" is thought to be better. They are physically larger though.
I don't know what you have access to but Sprague Orange Drops (715's 716's) are good and very friendly to the wallet. These are FILM/FOIL/Polypropylene. Measure and read the specs to make sure they will fit?
Your caps are probably MYLAR (polyester... popular in that era)... they may sound fine just the way they are.
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