p68 power supply questions

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Hi guys,
I have gust finished my p68 500w amp, and am busy starting the power supply. Here in isreal i cant get 100v caps for the power supply, the max i could find is 63v....:(
So I put this schematic together...
will it work like this?:):confused:
Thanks,
Kinser
BTW im only 14 years old...
 

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Thanks mikeks,
But is this circuit ok? i mean by connecting the caps in series?
am I right if by connecting two 63v capacitors on each rail in series will make a total of 126v on each rail? and will be more than enough for each rail?

Thanks agian
Kinser
 
Money is a problem for me:

I have found some 4700-8000uF caps on Ebay but the price for one of these caps is 15-30$ times that by two pluse the shipping fee..
it is alot of money for me...
cant i do something like this?(the attached image)
Thanks
Kinser
 

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Just another Moderator
Joined 2003
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Hi Kinser,

I think what you have posted will work fine, but I also think that if you can get 100V 6800uF in your price range that it would be better to just go with two of them.

I don't know whether there will be any I'll effects having that config of caps. Others with much more experience in such things can probably be more help :)

Have you checked out http://www.rsisrael.com ???

unfortunately they don't have prices online, but you could ring them.

part number 381-9172 should do the trick very nicely, but I expect the price will be out of your budget range.... you could ring them though and find out, they can probably offer alternatives too :)

127-523 might also do the trick and would I suspect be cheaper....

Tony.
 
If you put the electrolytic caps in series you should also put a parallel resistor across each one. Electrolytics have a very wide tolerance range and the voltage division at low currents will be inversely proportional to their actual capacitence values. I suggest 2K5 2W resistors. They will draw only about 25mA, so will not compromise the supply capability.

John T
 
JTT said:
If you put the electrolytic caps in series you should also put a parallel resistor across each one. Electrolytics have a very wide tolerance range and the voltage division at low currents will be inversely proportional to their actual capacitence values. I suggest 2K5 2W resistors. They will draw only about 25mA, so will not compromise the supply capability.

John T


A-ha

Somebody did mention it. The series caps may not have equal voltage across it, but the resistors will. If max voltage is exceeded across one, then BOOM, and if it shorts, then BOOM there goes the other one.
 
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