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Old 2nd April 2010, 03:43 PM   #11
tinitus is offline tinitus  Europe
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I just looked at new Vishay/BC 101 with screw terminals

If I remember right it was like 4000 hours at 85 celcius
Tho at 40 celcius its estimated 400.000 hours = 45years
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Old 2nd April 2010, 11:43 PM   #12
wwenze is offline wwenze  Singapore
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Since the topic has shifted to temperature somehow, while at it may I ask...

The temperature theory, does it apply for 85 vs 105 degree rated capacitors ? i.e. 105 degree capacitors last 100x longer compared to 85 degree capacitors at say 60 degrees.

Of course, I know in reality the lifetime is affected more by other things than temperature rating, but would be interesting to ask.
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Old 3rd April 2010, 05:42 PM   #13
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Caps are rated for life at temperature, so you might get ~4000 hours from whatever at its rated temperature. It follows that derating will save life, so it should be true that 105C+ caps last longer at the same temperature.

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Old 3rd April 2010, 09:16 PM   #14
tinitus is offline tinitus  Europe
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One might think that, and I have too

But maybe it just means they are tested to endure and survive tougher conditions
They are tested and specced to do that
But it doesnt mean that the lesser 85degree doesnt survive the same, its just not been tested to do that
Might even be the exact same cap, just with a different label

To be realistic, 4000hours is like nothing, other than it means the test cap has survived exstreme heat conditions

I dont know, but if the heatsinks are 50degree, maybe the air inside the box is no more than 40degree

And who knows how amps are in 10years
Anyway, the real cap killer seems to be instability, oscillation can boil a cap
Please dont ask me why

I dont know why, but I always get suspicious whenever I see fancy black and gold labels
Why we fall for that is beyond me, but we do
Im no better, cause I think the ordinary looking Panasonic with black and white looks boring, but they are probably just as good as any

Now, the true quality is to me blue, and blue probably because it comes from the old days when Spraque was the ultimate cap, and being blue
Funny ehh, quality being about colours
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Old 4th April 2010, 12:21 AM   #15
wwenze is offline wwenze  Singapore
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Quote:
I dont know why, but I always get suspicious whenever I see fancy black and gold labels
My two favorites, Panasonic FM and ELNA basic For Audio, are both gold on black. =.=

FC and its blue color looks good too. But it being much smaller compared to the rest makes me feel that it is "slower" (do higher power density caps always have higher ESR?)
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Old 4th April 2010, 08:27 AM   #16
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I would expect so. Less room for the conductive parts (more foil / electrolyte). Check the datasheet.

FYI, I haven't seen a single snap-in that was "slow". Firing a random 220uF 400V into a xenon flash tube, I got a discharge two times faster than any film capacitors I tried (e.g., motor run). Typical discharge for a motor run cap, 20-30us. The snap-in did it in 10. General purpose electrolytics, on the other hand, can be painfully slow: a 100uF 350V axial took miliseconds to discharge, equivalent to 2-3 ohms ESR -- which is as the datasheet states. YMMV, especially for low voltages.

Note that none of this actually matters for most audio purposes. Indeed, I can think of situations where low ESR might make an amplifier unstable. I've also seen switching supplies go unstable when too little ESR is used (for instance, the ESR might be part of the control loop, so it effectively provides derivative feedback, stabilizing the circuit). A proper circuit is engineered on all levels, including capacitor selection; don't just grab something that looks good (or advertizes anything about "sonic quality", which should be a big red flag that something ain't right here), use the component appropriate for its circuit.

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Old 22nd April 2010, 09:12 PM   #17
tinitus is offline tinitus  Europe
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Anyone know anything about these very cheap Jianghai caps ?

33.000uf/25V costs only 5 EUR....sold through Conrad Germany, so I suppose they will at least work
10.000uf/25V less than 2 EUR, 1.7 to be exact
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Old 9th September 2011, 02:14 AM   #18
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Poptart most propable knows this but for those that dont I would like to add that every 10 deg of temperature decrease can roughly double the life of almost every component.
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Old 9th September 2011, 03:01 AM   #19
tinitus is offline tinitus  Europe
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yes
and according to Panasonic 'test manual' the specced temperature ratings means that its been exposed to that excact temperature, for a short period
after that it will last the specced life time at the much lower 20 degree

so I think there is wide misunderstanding of what specced life time really means
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Old 9th September 2011, 03:22 AM   #20
erin is offline erin  Australia
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Old thread.... but anyway.

So here is my question.
If an electrolytic is rated for 4000 hours at 85 degrees. And then it sits unused for 5 years at around 20 degrees, is it still good to use?

I think it is OK to use, but I wonder how long it's life would be when voltage is applied and it sits next to a voltage regulator, and the cap gets to perhaps 40 degrees?

Next scenario is that the cap sits unused for 10 years?

Is it still good?

Now, I have no intention of purchasing these, but, what about those new old stock black gate capacitors that people advertse on ebay or other online parts shops?

They are quite old now. Are people who buy these spending money on shrivelled up old prune capacitors? Or are they still good?

Last edited by erin; 9th September 2011 at 03:25 AM.
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