I have a fisher tube amp that has a can capacitor 80uf 500v. I'm wondering why a can capacitor would have been used for a single value capacitor. Aren't can caps usually multi capacitors? Also I can't find a replacement can cap so will 80uf 450v sprague aluminum electrolytic work?
Single value can capacitor
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Bassblaster
Super Member
Maybe. depends how much voltage actually runs through it.
http://www.mouser.com/ProductDetail...=sGAEpiMZZMtZ1n0r9vR22fvNoVj4viFMkGvwgMMrVzk=
82uf snap-in can should work. You'd need a clamp though.
The single section cans existed for voltage doublers sometimes. It also may have been a space consideration. Figure that any under-hood cap of the era would have been about the same physical size as that can is, and there simply may not have been the room for it. My big Bogen amps had 2 single section caps for the doubler, and there is absolutely nowhere to put stuff underneath. They were replaced with modern snap-in type caps in a clamp to make it all work and fit.
The single section cans existed for voltage doublers sometimes. It also may have been a space consideration. Figure that any under-hood cap of the era would have been about the same physical size as that can is, and there simply may not have been the room for it. My big Bogen amps had 2 single section caps for the doubler, and there is absolutely nowhere to put stuff underneath. They were replaced with modern snap-in type caps in a clamp to make it all work and fit.
Bassblaster
Super Member
Hmmm. i would be very careful buying electronic parts from china
nj pheonix
Lunatic Member
Is it insulated from the chassis?
If not you could probably get a multi section at 500 (525? ) you can tie 2 or more sections together
If not you could probably get a multi section at 500 (525? ) you can tie 2 or more sections together
nj pheonix
Lunatic Member
Thain,
It's probably a better cap to boot. Doesn't necessarily look stock. it matters to some
It's probably a better cap to boot. Doesn't necessarily look stock. it matters to some
I'd buy the dual 40uf / 500V JJ version. I've had VERY good luck with these JJ 'can' caps! Not the pretty aluminum like the OE stuff.....but still not bad looking. And, in having used perhaps a hundred of 'em so far, I've yet to have one fail! FWIW....... Tom D.
WHOA, be VERY careful with that! Often if the cap has a cardboard sleeve it is because the can is not at ground potential! In a voltage doubler the "top" capacitor will have half the b+ voltage on the "ground". Exposed 250VDC is not a good way to start your day...
Which Fisher amp is it? That would help us give you more targeted advice.
Good point Ross! I'm thinking that an 80uf @ 500 V is likely not a voltage doubler type caps.....as those are generally down around 250 to 300V, and with a uf value that is much higher. If the OP is correct that this IS an 80uf @ 500V, then I'd say it's likely to be a PS filter cap with the 'can' at chassis ground....but a review of the schematic should confirm that. And, would be 'good practice' to review that document prior to any 'poking or probing' around in there. That said, I've run into a lot of cardboard covered caps that were NOT isolated.....just cardboard covered. But, that cardboard ought to throw up a red flag.....so.... worth checking into full prior to getting a shocking experience!
UNPLUG IT and leave it that way UNTIL you've FIXED IT. As for the REDPLATING TUBE, it's more likely a bad cap causeing the tube to glow RED. Build yourself a DBT (Dim Bulb Tester) and run it thru that 1st to rule out any shorts.
I would recommend this thread move to the FISHER FORUM as it's specific to a FISHER UNIT.
I use the DUAL 50/50 500v JJ can in my FISHER MONO receiver units with no problems. All of them are running GZ-34 and have btwn 465 and 470v going in to the 1st section of the cap. Get 3 of them and you can take care of C1, C2(A&B), and C3(A&B) for less than $25.00 https://www.tubesandmore.com/products/capacitor-jj-electronics-500v-5050-f-electrolytic $7.88ea. They are clamp mounted, so you'll need to drill 2 holes for the clamp. https://www.tubesandmore.com/products/capacitor-clamp-1375-diameter $1.54ea.
I would recommend this thread move to the FISHER FORUM as it's specific to a FISHER UNIT.
I use the DUAL 50/50 500v JJ can in my FISHER MONO receiver units with no problems. All of them are running GZ-34 and have btwn 465 and 470v going in to the 1st section of the cap. Get 3 of them and you can take care of C1, C2(A&B), and C3(A&B) for less than $25.00 https://www.tubesandmore.com/products/capacitor-jj-electronics-500v-5050-f-electrolytic $7.88ea. They are clamp mounted, so you'll need to drill 2 holes for the clamp. https://www.tubesandmore.com/products/capacitor-clamp-1375-diameter $1.54ea.
Let me know if you want it to move to the Fisher Forum