Lifespan of Capacitors

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Ricky64

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Thinking about picking up a used Soulution 725. Curious if the concept of capacitor fatigue is a real issue?
Anyone actually audibly observe this phenomenon? Do companies Recap older pieces? Or have a way to test for need for this?
 
Ricky64 said:
Thinking about picking up a used Soulution 725. Curious if the concept of capacitor fatigue is a real issue?
Anyone actually audibly observe this phenomenon? Do companies Recap older pieces? Or have a way to test for need for this?
Click to expand...

Not familiar with the term capacitor fatigue, but capacitors will go bad regardless of what you call it. It may take 15 years or longer, but it can take much less: I had caps go bad in a 3 year old sub! Usage, heat, and voltage play a factor.
Sometimes you can hear that something is amiss (hum or noises, for example); but they can go bad and damage other parts without much warning.
Capacitors can be tested with a multimeter/tester to check if they are working properly.
 
Many companies will bring a piece up to spec for a price. You'd have to check with the particular company to see if that is something they offer and how it works with them.
 
With the exceptions of some electrolytics and truly ancient paper cap, then more than 1/2 century.
There was a period of more than a decade, where many electrolytics had bad chemistry and failed quickly, but newer one should be good for 30 years.
 
I'm going to cry when the electrolytic capacitors die in my custom hybrid amplifier's power supply. Those 16 Black Gate FK 10,000 uF cost around $4K 20 years ago and are now unobtainum!

Oh, it's companion amp isn't much better. It has 4 x 37,000 uF Siemens Sikorels.
 
The EE that rebuilt my amps and is going to do some work on my Pre has frequently talked about this subject.

He said that by testing most all caps start to deteriorate after 4-5 years though their life is longer. The caps in the amps were 17 years old and measured poorly.

The warranted life by most manufacturers is not very long.
We tried to purchase some longer life Caps for my amps but I would have had to purchase 2000 at around $250+ each. That math didn't work. Ended up with 8 year expected life around $150 ea.
 
So we have a number of different opinions on this. Anyone feel these are considerations for them when they make a purchase? Does anyone purchase only new because of legitimate concerns about this?
 
brad225 said:
The EE that rebuilt my amps and is going to do some work on my Pre has frequently talked about this subject.

He said that by testing most all caps start to deteriorate after 4-5 years though their life is longer.
Click to expand...

That's interesting Brad. I wonder how long it takes before the degradation is audible vs. measurable?
 
MichaelsMinute said:
I wonder how long it takes before the degradation is audible vs. measurable?
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I guess that would totally depend on the environment around the capacitor. Continued increase in the internal core temperature due to electrical overstress will cause degradation within the capacitor. . If you can measure it, well depends on when you measure it. But of course a bad cap, well can hum, click or just flat out blow with a "bang". So it depends. I guess someone needs to try it out.
 
Ricky64 said:
So we have a number of different opinions on this. Anyone feel these are considerations for them when they make a purchase? Does anyone purchase only new because of legitimate concerns about this?
Click to expand...

Not this per se, but I do purposely purchase gear I feel I'll have a better chance of being able to get repaired/supported in the future vs a more unique/obscure brand that may be gone in a few years.
 
brad225 said:
The EE that rebuilt my amps and is going to do some work on my Pre has frequently talked about this subject.

He said that by testing most all caps start to deteriorate after 4-5 years though their life is longer. The caps in the amps were 17 years old and measured poorly.

The warranted life by most manufacturers is not very long.
We tried to purchase some longer life Caps for my amps but I would have had to purchase 2000 at around $250+ each. That math didn't work. Ended up with 8 year expected life around $150 ea.
Click to expand...

Normally a cap of reasonable quality will go about 20 years even if there is heat (as long as there isn't too much heat).

If these parts were in a solid state amp I'd be concerned. Caps in solid state amps tend to last longer since there is less heat than in tube amps. So in a solid state amp 30 years is common. Caps failing in only 8 years were defective parts unless operated outside their recommended specs.
 
Failure is different than optimal sound performance. I believe the original question was if there was a sound difference not the failure of the caps.

I have heard a difference between new and old caps in a re-capped amp. However, since the degradation happens over a lengthy time it is very hard to hear anything unless you have an amp of the same vintage with fresh caps to compare it to. I had 2 amps that sounded the same and was skeptical so I re-capped one of them and heard the difference. I went ahead re-capped the second amp.
 
Heat, and how close to maximum voltage parameters the capacitor is run. Of course there are caps that were not designed well in the past. Modern capacitors, under temp max, and under max voltage, will last a good while. (20-30 years).

Run hot, in temp, and voltage, will shorten lifespan. Exotic dialectrics make for a whole other issue.
 
Pretty much what Bones13 said.

It really matters what type of circuit the caps are in and how they are used. There are circuits that use really cheap, small caps that will last upwards of 30 years simply because they are being utilized well below their max ratings, which generally also means they're subjected to very little to no heat.

And of course, my thing is that I'm a strong believer of keeping gear powered up 24/7, which I have been doing for 20+ years now and I have yet to have a single piece of gear faulter due to capacitor failure. In fact, I have had next to zero gear failure of any kind since leaving the system running 24/7.
 
Mark Levinson had a real issue with caps in their No. 331/332/333's back in the 90's. IIRC they'd replace them under warranty even if the caps hadn't failed yet. Unfortunately I was unaware of the problem (no ML/dealer notification) until after my amp was out of warranty. Repair was an expensive proposition. Fortunately my unit never failed while I had it (light use, sold 2016).
 
atmasphere said:
Normally a cap of reasonable quality will go about 20 years even if there is heat (as long as there isn't too much heat).

If these parts were in a solid state amp I'd be concerned. Caps in solid state amps tend to last longer since there is less heat than in tube amps. So in a solid state amp 30 years is common. Caps failing in only 8 years were defective parts unless operated outside their recommended specs.
Click to expand...

Ralph-Did you mean to say tube amp in the sentence I bolded?
 
mep said:
Ralph-Did you mean to say tube amp in the sentence I bolded?
Click to expand...

Not directed at me of course, but my 2 cents is that it shouldn't matter whether caps are in a SS circuit or a tube circuit. As long as the caps are within a safe operating margin and exposed to minimal heat, they should last just about as long in either.
 
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