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-   -   Computer grade caps (http://www.diyaudio.com/forums/pass-labs/6101-computer-grade-caps.html)

joke 17th September 2002 05:09 PM

Computer grade caps
 
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)...so whats the diference ? ...can I use those Philips or should I go for computer grade capacitors ?

schizeckinosy 17th September 2002 05:55 PM

Apex Jr.
 
Hi,

Those Phillips caps sound like the ones Apex Jr. has. They are cheap because Steve gets great deals on the surplus he buys up. I bought a boxfull a while ago and think that they should be great caps.

Cheers, Dan

UrSv 17th September 2002 05:59 PM

As always though remember shelf life and check the manufacturing date.

/UrSv

fcel 17th September 2002 06:02 PM

So what is a acceptable shelf life/manuf date? I've always wanted to know.

joke 17th September 2002 06:04 PM

Yes I faund them on the apex jr... So than I should go for them...
Thanks

UrSv 17th September 2002 06:15 PM

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.

/UrSv

schizeckinosy 17th September 2002 07:24 PM

however...
 
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

joke 17th September 2002 07:49 PM

Thanks for your replay people , but can you explain me what is computer grade capacitor ???
Thanks

joke 17th September 2002 08:03 PM

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 ...

Apex Jr 17th September 2002 08:25 PM

Capacitor types
 
FYI.......
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
Electrolytics.
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.
Steve


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