Computer grade caps

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Hi to you oll ... I have one question about power suplay capacitors... I'am building Aleph 4 or 2 ( don't know jet ) ... The question is ...
What is Computer grade capacitor and what is the diference betwin normal electrolitic ones ???
I found Philips 26000uF/75V caps but it doesn't say it's computer grade for 6.95 USD and I found on RS-electronic BHC 22000/63V computer grade for like 30 USD ...( it's big diference in price so I'am confused , I know the normal price is like 20-30 USD) whats the diference ? ...can I use those Philips or should I go for computer grade capacitors ?
Well as far as I remember (and I could VERY well be wrong) RIFA specifies shelf life of PEH169 (excellent cap) to 10 years. I think I have read the same numbers from Nichicon. Personally I am reluctant to buy anything older than 5 years if is not dirt cheap.


I tested the 10,000uf caps in a 25+ year old SAE amp that I am rebuilding into a Leach amp, and they are still good. I charged the PSU up one day, and the next day the voltage was still pretty good (about 50% of full I recall), and I was able to spot-weld steel with them. :D The thick layer of dust in the amp probably contributed to the leakage.

I seem to recall reading (from Mr Pass?) that older big caps frequently stay good even if they dry up.

Cheers, Dan
I just went to apex Jr page ... and there it is ... with the big letars... Computer Grade ... Philips 26000/75V ...
I didn't see it firs time ... only that it's great for solid state amps...
so thanks to you people out thare ones again ...
Joined 2002
Paid Member
Capacitor types

Computer Grade are caps that look like beer cans,
either with the screw terminals or PC Leads, At one
time they were in the older computers.
There's also the snap in types that are a smaller version
of the computer grades: And than the Radial and Axial
I won't forget the Disc's, Poly types, HV, and the variations
from there.
BTW...The 26,000uf 75V caps date code is 9235
35th week of 1992.
The one and only
Joined 2001
Paid Member
Computer grade is a phrase left over from the good old
days of computing when they had linear supplies that
drew tons of amps all day long.

Nowadays they all seem to have switching supplies and
much smaller capacitors. The big cans are still readily
available, however industry in general has switched over
to PC mount snap in caps.

These work fine, but don't have the aesthetic appeal of
the big barrels.



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Joined 2002
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Computer Grade Caps

I see your picture; and the differance to think about is the
size. The older the date code the larger they will be.
I suspect your 30,000uf 75V cap is 3" Dia and about
5" high. My 26,000uf 75V are only 2" dia and 4 1/8" high
And there still making them smaller. Technology changes.
Apex Jr
Has anyone held a RIFA (from Sweden of course!) cap in your hand? Shake them! What do you hear? Fluid inside which flows! The RIFA caps has lots of electrolythic fluid so they will last for a very long time.

To be short:

Computer grade:

Can take very much current
Lasts long

Expensive or very expensive

Sonic properties, I have no idea.
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