Capacitor lifespan

[BoogieZK]

Like anything, a cap can go bad in a day or 50 years. But changing them as a matter of routine is silly. Apparently you didn’t, so not pointing fingers at you. But for those who do change them after a certain amount of time whether they’ve gone bad or not, hey, spend your money foolishly if you want.

Ha yes of course, replacing a part means i know it has to be changed, it's not a guess!
BUT I have too add that if a component is given for lets say 1000hrs and if i exceed this lifespan AND if i really need to have this electronic device to be fully working, i'll replace it.
I worked for trains where Preventive maintenance is key, you don't want any equipement to fail during people transportation.

Basically my routine too.
1) Look for burnt components.
2) Loose connections.
3) Relays, switches (burned / oxidized contacts).
4) Caps.
5) Actual troubleshooting.

Ho yeah, it's so natural to look at something burnt i forgot to mention it.
And yes Relays and switches.

Actual troubelshooting consist for me in:
Short-circuit on power supply
Shorted or bad transistors
Diodes
....

but it all depends on what is troubleshooted.

 

[skycruiser]

Root Cause Analysis.

If you need to replace a capacitor, you also need to do the above.

 

[portpc]

I've been selling electrolytic caps for a living for 35 years.
I deal with several successful Amp Mfgr's who only want specific older date code electrolytics because they just work correctly - they like the color or they don't wish to change the recipe for Diet Coke.

If they were receiving a high level of returns due to cap failure I'd be one of their first calls - Hasn't happened.

 

[PeaveyPlayer]

A few of the Peavey members have change caps in their preamp’s on board I’m wondering if it’s just placebo then

I’ve also graphed a difference when changing caps

 

[Crackle]

I have a Heathkit GR-91 receiver that was made between 1961 and 1963. That puts it between 61 and 63 years old now. Last year I took it to a radio shop to have the electrolytic capacitors replaced and have the radio aligned. The technician diagnosed it and determined the original capacitors are all still within spec. He did the alignment and I didn't have to pay for anything unnecessary.

 

[bigdaddybass12]

with age there is a dissipation factor with capacitors. Also, the capacitor 'drying out' (dielectric materials become brittle ). But one factor of the life span is the temperature it operates. I recently sold a 60 or 70 yr old radio that worked perfect. I have a pro camera flash that is 35 yrs old, charges up & flashes as new. I would say regular use will help extend the life to avoid the cap from developing a memory. Rough handling of your equipment and a voltage surge adds to failure. . The surge could come from as simple as plugging in your bass with the equipment (pedal, amp etc) being turned on at the time. Finally a under-rated cap being used. We had smaller size power supplies with the caps the size of soup cans, it was over-kill but no issues. Did take a long time to turn off w/o a load.
Mr Horse, I know this is not very technical answer!

 

[Tassieviking]

I have seen lots of electrolytic caps fail when I worked as a maintenance electrician in industry, 16v electros do not last long when they are wired into light switches in the maintenance lab.
It sure made some people jump, please note this is not recommended as something anyone should ever do.

 

[dbsfgyd1]

I keep hearing the "all electrolytic capacitors" go bad preaching, the pundits stating that this varies from 10 years to 30 years yet in my experience on quality products 50+ years is a fairly easy metric to achieve. I have been accused of being ignorant, a dummy, and a moron because I don't agree with the mythology of old wive's tales.

I have provided some example calculations taking the data right off of capacitor data sheets and have arrived at calculated lifespans well in excess of 50 years, but these numbers simply aren't understood by the superstitious among us.

Here's the reliability numbers for a small power supply I was looking at, the mean time before failure is 3 million hours. There are several electrolytic caps in this power supply and 3 million hours is well beyond 200 years of continuous operation.

In general, probably 95% of all electrolytic caps replaced are perfectly good and will continue to be good for decades.

View attachment 5326378

In all my years and with all the different amps (not to mention basses) I’ve owned, I’ve had one cap fail. It was on an Eden Nemesis RS-320 combo that I bought used and was about 15 or so years old at the time. Quite a sound when it let loose..LOL!!

I agree with your premise, it’s not common.

 

[gtmalone]

I keep hearing the "all electrolytic capacitors" go bad preaching, the pundits stating that this varies from 10 years to 30 years yet in my experience on quality products 50+ years is a fairly easy metric to achieve. I have been accused of being ignorant, a dummy, and a moron because I don't agree with the mythology of old wive's tales.

I have provided some example calculations taking the data right off of capacitor data sheets and have arrived at calculated lifespans well in excess of 50 years, but these numbers simply aren't understood by the superstitious among us.

Here's the reliability numbers for a small power supply I was looking at, the mean time before failure is 3 million hours. There are several electrolytic caps in this power supply and 3 million hours is well beyond 200 years of continuous operation.

In general, probably 95% of all electrolytic caps replaced are perfectly good and will continue to be good for decades.

View attachment 5326378

I think the problem with electrolytics failing is lack of use for multiple years. In use, assuming the circuit is in good order, the life span should be really long. The other thing is the quality of caps has improved considerably since the days of vintage gear.

I have caps in a B15 and a Dynaco ST70 amp that are close to 20 yrs old. Both amps are used pretty regular and have no problems with hum or noise.

 

[Gervais Cote]

Electrolytic capacitors have a lifespan in terms of hours vs temperature.
Many are 5000 hours at 85C degrees but it can also be more than that.
And as a rule of thumb, the highest running temperature, the shortest lifespan.

 

[Crackle]

I have seen lots of electrolytic caps fail when I worked as a maintenance electrician in industry, 16v electros do not last long when they are wired into light switches in the maintenance lab.
It sure made some people jump, please note this is not recommended as something anyone should ever do.

I was 17 years old and had my first car. I had installed a cassette deck and a pair of 6x9 speakers and a power amp. I was listening to the Ozzy Osbourne - Randy Rhoads tribute album at ear-bleeding volume while driving down a residential street. Specifically the guitar solo section of the recording. I heard what I thought was a gunshot and legitimately thought someone had a gun after me. I turned it down and got the hell out of there.

The next day I noticed one of the speakers had lost its high end. Once I removed the speaker, I found it full of trash from an exploded electrolytic capacitor. That was the sound of the gunshot. It's amazing how much noise an electrolytic capacitor can make when it goes off.

 

[Tim Skaggs]

I have a 1970 Ampeg V2 guitar amp with all original parts except tubes and even the original tubes still work, they are just showing a little weak on a tester. Caps are still good or at least the amp is quiet…

 

[agedhorse]

And yet on many things i have to repair (not only audio) there is caps loosing their values or leaking.
For example, I repaired a Koch amp which had a bad set of caps resulting in wind noise in the speaker.

Or my actual Daikin AC/heater is failing when it's too cold outside because of bad MKP caps degrading the comm between out unit and in unit.
Life span? 4 years.

I'm not saying it's always the capacitors but i always check them quickly.
My check routine is in this order:
Isolation/ground
Connectors / cables
relays
capacitors
... and the rest.

If a bunch of caps care leaky, this indicates a more fundamental problem.

Electrolytic caps used for motor control (AC start and run caps) can degrade because of the type of construction, the ripple current and the environment (wide temperature and moisture) I wasn’t talking about this type of cap.

I agree with agedhorse - I think it's sacrilege not to that not all electrolytic capacitors are destined to fail after 10-30 years, especially in the well designed and high quality circuits he engineers. However, I think it should be made clear that caps can fail well before their time.

Some caps can operate for 50+ years... IF they're properly constructed with high quality components and put in a well designed circuit that's not subject to misuse (someone connecting the wrong power supply, connecting a 2 ohm load while turning all the knobs to 11, etc.) and not exposed to detrimental environmental conditions (heat, freezing cold, humidity, liquids, lightning, vibration, shipped via UPS / FedEx without padding, etc.)

Many years ago I was a victim of "the capacitor plague". A cap in my video card exploded. Easy fix, but the video card was only a couple years old.

A quick search at Invalid Link Removed shows there are some aluminum electrolytic caps only rated at 500 hours of lifetime. Yes, that's the bottom end of the scale, but obviously not all caps are intended to run 50 years.

Bottom line, some caps can run 50+ years, some can't.

The “capacitor plague” issue was pretty much unrelated to the audio and most industries actually. It was due to caps being manufactured using an incorrectly compounded electrolyte, the formula that was stolen turned out to be incorrect. It was a problem with specific parts made in Taiwan and China for the computer industry primarily.

The 500 hour number is misleading, there is a formula for each capacitor type that factors in operating temperature, ripple current, operating voltage and other factors that determines real world lifespans. These other factors can add 10x to 100X to the base lifespan spec.

Basically my routine too.
1) Look for burnt components.
2) Loose connections.
3) Relays, switches (burned / oxidized contacts).
4) Caps.
5) Actual troubleshooting.

Why not start with basic troubleshooting first?

What really "stresses" caps (note the quotation marks) is power cycling. Not saying this to discount whatever you said, hey?

That said, it does make *some* sense to check caps in older equipment. Not all audio equipment was built to a standard (never mind a mil standard). If you are scouring through yard sales and picking up older budget gear, for instance, it is sensible to do so. But yeah, it shouldn't be a blind replacement.

Power cycling doesn’t really affect cap lifespan all that much IME.

These are crucial. I have seen electrolytic capacitors tested according to manufacturers specs and not all did what they promised. Also, life time is heavily depending on the temperature they build up, and more heat means lesser live span, and that decreases fast when temperature rises.

Most caps I have tested have been well within their specifications. Temperature does have a big effect on lifespan.

I had a learning experience a few years ago fixing an old late 60s British 100 watt 4x EL34 Carlsbro that came to me passing signal but with a loud hum. I went for the classic blind replacement of filter caps, but it turned out that only the smaller electrolytic in the bias supply had actually failed, and the amp would have run quietly if I'd diagnosed first and replaced just that. I don't know if the half wave rectifier in many bias supplies is harder on them, perhaps.

Half-wave power supplies typically have higher ripple currents which can affect lifespan, but there are older cap styles which have shorter lifespans also. These caps haven’t been made in many years.

A few of the Peavey members have change caps in their preamp’s on board I’m wondering if it’s just placebo then

I’ve also graphed a difference when changing caps

All caps have a tolerance. It’s commonly +/- 10% to +/-20% on electrolytic caps. It is entirely normal for there to be some differences, not because of defects but just due to normal deviations from the standard value.

 

[Major Seven]

I have a Heathkit GR-91 receiver that was made between 1961 and 1963. That puts it between 61 and 63 years old now. Last year I took it to a radio shop to have the electrolytic capacitors replaced and have the radio aligned. The technician diagnosed it and determined the original capacitors are all still within spec. He did the alignment and I didn't have to pay for anything unnecessary.

This is my situation. I have A 60s national receiver that was in a ham shack, several ARC receivers from WW2
airplanes and a few 60s "hi-fi" audio amps (bogen, dynaco...) The ARCs were in an attic for 30 yrs cycling hot/cold over and over. The national at least was in a stable basement.
I see these guys who claim to use a variac judiciously to "reform the electrolytics" which sounds like vodoo
or something.
What I think I see here is if things look reasonably ok, just power it up and see.

 

[Major Seven]

I think the problem with electrolytics failing is lack of use for multiple years. In use, assuming the circuit is in good order, the life span should be really long. The other thing is the quality of caps has improved considerably since the days of vintage gear.

I have caps in a B15 and a Dynaco ST70 amp that are close to 20 yrs old. Both amps are used pretty regular and have no problems with hum or noise.

How is lack of use for multiple years a factor?

 

[agedhorse]

How is lack of use for multiple years a factor?

There is a factor in some electrolytic caps, but in my experience it’s way overblown.

 

[coy garcia]

I've had to replace a few in my '91 boogie 400+ but most likely from rolling it over cobblestone to a gig

 

[Thumpin6string]

I think that using caps that are barely able to handle their loads could be the problem, or in some cases they were just pushed past their limits due to another bad part. I repair mig welders and they use very large (beer can size) caps. I have found that the majority of the manufacturers run parts that are barely able to handle the max load of the welder. IMHO this is why they have poor duty cycles (10-20%) at maximum power and fail when pushed. The 2 main under sized items that fail are the caps and the diodes. In a 100 amp welder the diodes are usually 80-90 amps. When I repair them, I use larger amp diodes and the same goes for the caps. I will say that the caps fail less than the diodes do but replacing them with higher value ones usually make the welder run smoother and cooler.

 

[Tassieviking]

I think a lot of these myths many people think are real have a slight truth to them, many myths were started a long time ago when materiel and manufacturing techniques were not as good as they are today.
I am lucky that I started building electronic amps and other things in the early 1970's when the quality of components and gear was of a better quality then when many "myths" were started.

 

[J Wilson]

This is one more of those things where what the famous 'they said . . . ' has caused a lot of un-needed expense and aggravation. I was very sorry that 'They' found a much bigger audience and home on the internet and continue to spew uneducated BS 24/7, everything from what bass to play, what amp, and (my favorite) the mega $$$ cable industry, where the musical instrument biz is trying hard to catch up to the Absolute Sound crowd.

It's been a problem for me, though: I wear a 8 1/2 cowboy hat or a XXL motorcycle helmet, and I've blown out more than a few caps, hard to find the right bigger ones.