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What impacts the effective life of a capacitor?


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21 minutes ago, Islander said:

 

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.

 

Owner of a motorcycle dealership told me a sad story. Sixteen year old kid had his heart set on a Ninja 600. Had been working and saving for a couple of years to buy one. But he had never ridden a motorcycle. Owner tried very hard to talk him out of it, but the young man had cash in hand and money was tight. So the owner gave him a quick lesson in the parking lot, and hoped for the best.

 

The kid embedded himself in a bridge abutment, a half mile down the road.

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39 minutes ago, Edgar said:

 

Owner of a motorcycle dealership told me a sad story. Sixteen year old kid had his heart set on a Ninja 600. Had been working and saving for a couple of years to buy one. But he had never ridden a motorcycle. Owner tried very hard to talk him out of it, but the young man had cash in hand and money was tight. So the owner gave him a quick lesson in the parking lot, and hoped for the best.

 

The kid embedded himself in a bridge abutment, a half mile down the road.

 

I was thinking of a more basic 600 than a Ninja, but even the modern 300s and 400s are plenty for a beginner, who can learn to master the bike before trading up to something bigger and faster.  Most, but not all, of the riders who start out on bigger bikes than they should never fully develop the confidence and feeling of full control that is needed for the safest result.

 

In the early time when I started riding, I got a 180 Yamaha, which was fast enough to get me in trouble, because I soon learned that I could ride it at 110 km/hr (65 mph) nearly everywhere.  That led to a number of close calls, which I won’t get into here.

 

A couple of years later, I got a Yamaha R5 350, which could go 120 km/hr (75 mph) everywhere.

 

The point is, I was happy with a small bike, including my later Yamaha RD400 that was faster than some Honda 750 Fours.  Nowadays, many of the kids don’t want to be seen on a small bike, so they buy something they’re not ready for, sometimes resulting in the tragic end that you described.  This really applies to the big bikes as well, which are somehow affordable to some beginners.

 

In my case, it was 17 years before I got a 750, and that was mostly because a change in the racing rules made riding a 350 or 500 more expensive.  I was well ready when I got that FZ750, and we spent many fun and exciting years together.

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8 hours ago, Islander said:

 

I was thinking of a more basic 600 than a Ninja, but even the modern 300s and 400s are plenty for a beginner, who can learn to master the bike before trading up to something bigger and faster.  Most, but not all, of the riders who start out on bigger bikes than they should never fully develop the confidence and feeling of full control that is needed for the safest result.

 

 

I started with a Honda Mini-Trail 50, at age 11.

 

Many years without a bike at all, then graduated to a Honda 250 dirt bike when I got out of college. Dirt bike experience -- highly recommended even for street bike riders.

 

After that, a Yamaha FJ600. Great middleweight bike, at the time.

 

Only then did I go to literbikes, where I spent many happy years.

 

Now that I'm old, I'm looking for something small, that is actually fun to ride at less than triple-digit speeds. The KTM 390 Adventure looks very interesting.

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21 hours ago, Deang said:

More like buying an old Harley that needs work. It’s rare for someone to start replacing parts on a new loudspeaker.

 

There was a maniac on this forum back in about 2004 who bought brand new K Horns and then replaced everything.  Wonder whatever happened to him....

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Back to capacitors.  I recently bought and 10 yr old diy class A amp. I noticed it ran REALLY hot, not class A hot, but HOT.  I drilled about a dozen 1” holes in top which had helped a lot.  Any way to know if the power supply caps where prematurely degraded by the high heat environment? The skins seem to have shrunk and a very slight bulging might be seen?  It sounds pretty good, but, as always, can I change something and make it better? 
@Deang or others have perspective on this?

thanks! Ted

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On 6/29/2021 at 12:13 PM, Deang said:

 

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.

 

So I have the nice high quality and I think sealed caps in a paid of JBL Centuries.  At 50 years old I think they need to be replaced even if they can last long.  I need to replace the L Pads anyway.

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I have some 40 yr old CRC hermetically sealed caps that are still just fine. Pity I did not buy up a stock when CRC went out of biz. CRC caps were the caps of choice for aerospace gear, and IIRC they mentioned their caps were used on the Voyagers, still rockin' in the interstellar void.

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On 6/25/2021 at 5:46 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. 

Surplus Sales of Nebraska has a good sized listing of those old bathtub-style cans on their site. FWIW, earlier this year, I replaced a bathtub style cap in a piece of equipment at work. It looked identical to the caps I replaced in my Type A crossovers. I should have kept the box that the new one came in.

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