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What impacts the effective life of a capacitor?


Bulkogi
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I was wondering if leaving a piece of equipment unused, or seldom used, for extended periods of time might cause certain types of capacitors to dry out or otherwise fall out of spec more quickly than with regular use.

 

Not surprisingly, the question came up in connection with my Heresy II refurbishing project.  As I've posted, my H2s were made in 1989 and I purchased them used in 2001.  At the time of my purchase, they sounded great.  I had A-B compared them to the KLF 20s I owned at the time, and recall the H2s being a bit livelier in the treble and midrange with the KLF 20s having more extended bass and perhaps a somewhat more balanced top end.  I liked both very much, but never had room for both.  By 2003, I was married and the H2s were on long term loan to my mom.  But my mom never really listened to them unless Eunha and I were over and I was in the mood to play something, and over the years their top end became a bit dull and lifeless.  Hence my decision to send the crossover networks to Crites for the rebuild service and the decision to give the titanium diaphragms a whirl.  Now they sound fantastic again (both with the original tweeter diaphragms and with the Crites replacements).

 

Granted, the H2s are now 32 years old, but I hear from people who purchased even older speakers when they were new and have run them ever since without noticing any loss in performance.  Of course that could be the proverbial frog in the slowly boiling pot not noticing the real change in temperature, but I do wonder if keeping current running through capacitors more regularly might actually prolong their life span?

Edited by Bulkogi
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20 minutes. 😄 

 

It depends on the construction quality of the capacitor and environmental conditions. 
 

A fully protected film and foil capacitor can last 50 years. 
 

Most aren’t aware that many of the old cans used by Klipsch were WWII surplus, and some were almost twenty years old before they even went into the loudspeaker. 

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13 hours ago, Deang said:

20 minutes. 😄 

 

It depends on the construction quality of the capacitor and environmental conditions. 
 

A fully protected film and foil capacitor can last 50 years. 
 

Most aren’t aware that many of the old cans used by Klipsch were WWII surplus, and some were almost twenty years old before they even went into the loudspeaker. 

 

I never heard my 1974 La Scalas when they were new, but when I replaced the old tin can caps (stacked 3 high at one position) in them in 2006, the brightness and clarity improvements were immediate and obvious.  The crossovers also looked tidier with their new Sonicaps.

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Would like to think that a hardly used vintage SS integrated well made amp, that has sat in it's box in a dry, cool room, would sound just as well as when it was placed in the box. After, 10 or 20 years. 

At least, it appears to be the case with one I have.

Deoxit and the like, not always needed for controls.

In my case anyway.

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Heat, mainly...usually not an issue in home loudspeakers. The electrolyte in electrolytic capacitors slowly dries out whether they are used or not. Most 'lytics start high in value and slowly sink down below spec, even in "good homes." Dean is correct when he says sealed film and foil caps can last 50 or more years.The operative word is sealed, as in hermetically sealed in metal with metal to metal or metal to glass seals. 

 

in 50 years of audio, I have encountered exactly one (1) crossover cap that was "audibly bad" and it was about 30 years old (a non-polar lytic). Now, I have replaced old caps with ones that were "'audibly better" as well as giving peace of mind stability due to more modern construction.

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36 minutes ago, boom3 said:

Heat, mainly...usually not an issue in home loudspeakers.

 

Unless you solder them into place with a 260W Weller soldering gun.

 

(Sorry, couldn't resist an obscure reference to an ancient thread.)

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C'mon   ,  there is no way that the larger Aerovox  cans used in the mid to late 70's Aerovox  were WWII  production ,  the manufacturing  date codes should be stamped on the cans ,and  PWK  would never  use 30 year old capacitors in his brand new crossovers -

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On 6/25/2021 at 3:46 PM, Deang said:

20 minutes. 😄 

 

It depends on the construction quality of the capacitor and environmental conditions. 
 

A fully protected film and foil capacitor can last 50 years. 
 

Most aren’t aware that many of the old cans used by Klipsch were WWII surplus, and some were almost twenty years old before they even went into the loudspeaker. 

Oh man, I have sealed caps in JBL L100s, thought I was ok until I realized that they are 50 years old.  Time for new ones. 

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18 hours ago, RandyH001 said:

C'mon   ,  there is no way that the larger Aerovox  cans used in the mid to late 70's Aerovox  were WWII  production ,  the manufacturing  date codes should be stamped on the cans, and PWK  would never  use 30 year old capacitors in his brand new crossovers.

 

I've never noticed date stamps on those, but then again, I never looked for them either.

 

Here is what I have from my notes.

 

"Prior to 1971 Klipsch used surplus PIO types (decades old) that had glass hermetic seals, these type seldom fail. After a short (failed) experiment with Mylar types new PIO types were obtained, but the seals do not look to be glass hermetic, and they fail (after a couple of decades of use)." -- DJK


"The older oil caps were WWII military surplus, and were hermetically sealed. Those have a much better life than the ones Klipsch had custom made for them in the mid 70s (and later). I've seen PIO WE oil caps from the 30s still be OK, they're hermetic with glass seals too. PIO Vitamin Q caps are hermetic with glass seals." -- DJK


"Prior to 1971 PWK used whatever cheap surplus oil caps he could get his hands on. After that stock was exhausted he went to some cheap Mylar caps. Those were so dreadful he had new oil caps made. Later he moved back to Mylar." -- DJK

 

DJK (Dennis) used to be a Klipsch dealer. I'm looping in @Marvel on the question of whether Dennis knew PK or not. I just don't remember.

 

Whether in an old post or during a phone call, Dennis told me PK had barrels filled with parts on the factory floor, and employees would dig for what they needed. Some built crossovers at home for extra money. He told me all of the capacitors were from surplus left over from the war. "Surplus" would be NOS in this context - not old used stuff.

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The old electrolytic will last longer then most think. I routinely replace all of them when restoring old electronics just because they do have a life limit of 15 years. Most trouble will be in the hard working PS section though. Film caps will hardly ever just outright fail. Just does not happen. Replacing old ones will sound different but that is also the case trying different new brands as well. The old saying "if it ain't broke why try and fix it" applies. In other words if you are satisfied with the sound you have just leave alone. One exception with the old oil filled ones laying on their side. If they leak replace them. 

 

Many on this forum are like those buying a Harley Davidson motorcycle. After purchasing a new one they go back to the store every weekend buying something new and different for their bike. At least that is what my best friend said who was a manager of a Harley, Suzuki store. When a Suzuki was sold they never saw them again. 

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1 hour ago, henry4841 said:

 

 

Many on this forum are like those buying a Harley Davidson motorcycle. After purchasing a new one they go back to the store every weekend buying something new and different for their bike. At least that is what my best friend said who was a manager of a Harley, Suzuki store

 look Ma , No Frame    ,  we're talking more than 100k$

the-winning-custom-bikes-of-the-amd-world-championship.jpg

 

 

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In the for what it is worth category. I used to use those nylon clips with cable ties when I reworked crossovers. Later on I had a reason to remove some and the sharp corners on those clips had pressed indentations on the side. I have no idea what that did to the capacitor values but ever since then I silicone them in place.

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3 hours ago, Deang said:

DJK (Dennis) used to be a Klipsch dealer. I'm looping in @Marvel on the question of whether Dennis knew PK or not. I just don't remember.

 

I don't know the answer to that. He wasn't a Klipsc dealer by the time I met him (through his brother) in the early '80s. I've been out of communication with him for a long time but I'll try to contact him to see if he has any insight.

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5 hours ago, 001 said:

 look Ma , No Frame    ,  we're talking more than 100k$

the-winning-custom-bikes-of-the-amd-world-championship.jpg

 

 

 

Err, where are the handlebars?  And with no stand, you’d have to lean it against whatever was available.  That may not even be a kinetic sculpture, which to me requires that the piece at least be rideable.

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6 hours ago, henry4841 said:

The old electrolytic will last longer then most think. I routinely replace all of them when restoring old electronics just because they do have a life limit of 15 years. Most trouble will be in the hard working PS section though. Film caps will hardly ever just outright fail. Just does not happen. Replacing old ones will sound different but that is also the case trying different new brands as well. The old saying "if it ain't broke why try and fix it" applies. In other words if you are satisfied with the sound you have just leave alone. One exception with the old oil filled ones laying on their side. If they leak replace them. 

 

Many on this forum are like those buying a Harley Davidson motorcycle. After purchasing a new one they go back to the store every weekend buying something new and different for their bike. At least that is what my best friend said who was a manager of a Harley, Suzuki store. When a Suzuki was sold they never saw them again. 

 

That why you try to sell them a 600 first, so that they’ll be back in a year or two to buy a 1000.  After that, very few will trade up to a Hayabusa 1300.  But a few is still better than none.

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