I am presently working on a Parasound HCA-1000a. The amp plays well but all 4 power supply caps are bulged. They are presently Elna for Audio 10,000uF 63V and measure 35mm x ~50mm. There is no room to increase diameter but it looks like I could go to about 75mm high. I am considering upgrading the caps in terms of capacitance (12,000uF or 15,000uF) or voltage rating.
There seems to be quite a few options for replacements. The first thought was to get direct replacement Elna for Audio caps, however, it strikes me strange that a cap touted for Audio would be used for power supply filtering. Nichicon and others do this as well. There are found in many popular amplifiers. Are these caps really better for audio amplifier power supplies vs more general power supply caps form Panasonic, Sprague or Vishay?
From what I can tell from the specs, the Panasonic TS-UP has higher ripple current rating and lower ESR than the Elna. Is there a reason that it would not be a better choice?
Thanks
Stan
There seems to be quite a few options for replacements. The first thought was to get direct replacement Elna for Audio caps, however, it strikes me strange that a cap touted for Audio would be used for power supply filtering. Nichicon and others do this as well. There are found in many popular amplifiers. Are these caps really better for audio amplifier power supplies vs more general power supply caps form Panasonic, Sprague or Vishay?
From what I can tell from the specs, the Panasonic TS-UP has higher ripple current rating and lower ESR than the Elna. Is there a reason that it would not be a better choice?
Thanks
Stan
Careful where you source Elna's from as there are a lot of counterfeit ones out there. Personally i would fit the Panasonics, or Nichicons.
Why were they bulging? What voltage are the rails? If there more than 50 volts you might want to increase the cap voltage.
remove the plastic cover on the cap and you will never know the difference...😀
agree on upping the height to 75mm.....
measure your actual rail voltage, the new caps should be rated at, actual rails x 1.2 or more...
low esr caps are sought after in smps psu's....higher ripple current ratings are always desirable...
agree on upping the height to 75mm.....
measure your actual rail voltage, the new caps should be rated at, actual rails x 1.2 or more...
low esr caps are sought after in smps psu's....higher ripple current ratings are always desirable...
Also, you may want to get the highest temperature rating with the longest life, something like 105C and 5000 hours. Don't let that life value scare you (it comes out to seven months!), that's for it running in a switching supply deep inside computer equipment at hotter than boiling water. At the temperatures they're likely to see in the amp (maybe 40-50C) they'll last many, many times longer (as in several decades). Thus, you (as in you personally, as opposed to your descendants) may never have to replace these caps again.
Here we go (scroll down to see a listing of 10,000uf at 63V caps):
Aluminum Capacitors | Capacitors | DigiKey
Looking through that table, t appears all the "goodness" factors go up together (longer lifetimes at higher temps also have higher ripple current and lower impedance), and of course price goes up along with them. I don't know exactly how lifetime varies with temperature, but something with a 1000 hour at 105C rating will last substantially longer at 85C, and even longer at lower temperatures.
Okay, I googled, this looks interesting:
http://jianghai-america.com/uploads/technology/JIANGHAI_Elcap_Lifetime_-_Estimation_AAL.pdf
Looking at the graphs, for every 10 degrees C below the rated temperature, lifetime DOUBLES from the rated max-temp lifetime. That's only for a specific series of capacitors by that manufacture, but I think the general trend is typical of all brands of electrolytic capacitors.
Here we go (scroll down to see a listing of 10,000uf at 63V caps):
Aluminum Capacitors | Capacitors | DigiKey
Looking through that table, t appears all the "goodness" factors go up together (longer lifetimes at higher temps also have higher ripple current and lower impedance), and of course price goes up along with them. I don't know exactly how lifetime varies with temperature, but something with a 1000 hour at 105C rating will last substantially longer at 85C, and even longer at lower temperatures.
Okay, I googled, this looks interesting:
http://jianghai-america.com/uploads/technology/JIANGHAI_Elcap_Lifetime_-_Estimation_AAL.pdf
Looking at the graphs, for every 10 degrees C below the rated temperature, lifetime DOUBLES from the rated max-temp lifetime. That's only for a specific series of capacitors by that manufacture, but I think the general trend is typical of all brands of electrolytic capacitors.
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I'd always go for the lowest ESR over a 'for audio' label. Bear in mind that multiple paralleled smaller values normally gives better ESR (and ESL) than fewer large-valued caps. Using smaller caps allows placement closer to the point of demand, reducing in-circuit impedances further.
3K hours /85C/ 12Kuf /35X50mm - 10mm LS @ 63V Nichicon - 7.84$ -
LLS1J123MELC Nichicon | Mouser
Have "LS" series in both test supplies / abused high current amps - NO issues.
OS
LLS1J123MELC Nichicon | Mouser
Have "LS" series in both test supplies / abused high current amps - NO issues.
OS
IMHO, this question should be answered first.
50 V on a 63 V cap should not be any problem, so why did they bulge?
IMHO, no, it's mainly a marketing strategy. They know that when you pay 5 times the price of what its standard version will cost, you're going to hear the difference, even if there isn't any.
I'm in industrial electronics and there you don't see that kind of b*llsh... (sorry). Caps are selected based on what is required for the design. Usually that is a well-known quality brand (mainly BC/Vishay, Nichicon, Rubycon, Panasonic and Nippon Chemicon, and also Yageo) but nothing fancy, not even in equipment that is deemed high-end, even in industrial terms. When the times comes, I would gladly replace my "for audio" caps that Marantz put in my amp for any non-audio cap with suitable specs.
Standard caps should not be replaced by low-ESR caps arbitrarily. Keep in mind that changing a standard cap with a low ESR type can actually lead to problems, depending on the circuit (e.g. LDOs usually need a cap on their output with an ESR that is not too low to be stable).
Gives people peace of mind. People can find fault in everything like vaccines results in autism, and low ESR electrolytic can result in... something I guess, unstability? But when you say it is "for audio" and wowwwww it is designed for audio. Even better if you slap on the name of some British guy.
The people at Marantz and Elna must be laughing and crying at the same times. Engineers don't always have the say when it comes to this kind of things.
The people at Marantz and Elna must be laughing and crying at the same times. Engineers don't always have the say when it comes to this kind of things.
As @jitter says, just follow recommendations for industrial design and forget "audio capacitors".
Good capacitors usually have long working life at high temperature, for example if you find some model with 10.000 hours at 105C that is probably the best in class - High Reliability.
Also if you have space on PCB, choose capacitors with higher voltage (larger).
Good capacitors usually have long working life at high temperature, for example if you find some model with 10.000 hours at 105C that is probably the best in class - High Reliability.
Also if you have space on PCB, choose capacitors with higher voltage (larger).
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That is a good question. I am at least the 3rd owner of this amp so I don't know the history. I will check the rail voltages but I tend to believe that Parasound would have selected the components carefully. If the voltage is out of spec, perhaps there is another issue or possibly bulged from a power surge.
It seems that there have been some advanced in capacitor design, materials and manufacturing that allows for higher spec parts (uF, ESR, V, and temp) in smaller packages than were available 18 years ago.
Thanks again
Thinking about it again, you wrote that the amp is working well. That doesn't really go together with bulging caps that would have lost about all of their original capacity.
Often these will also leak electrolyte all over you precious board...
In images I googled, I see that those caps are the types with a plastic insulator disc on top of them. Sometimes it's just the plastic disc that shows a slight bulge, and the cap is actually fine.
Having said that, 18 years is long enough a time for electrolytics to suffer from ageing.
Often these will also leak electrolyte all over you precious board...
In images I googled, I see that those caps are the types with a plastic insulator disc on top of them. Sometimes it's just the plastic disc that shows a slight bulge, and the cap is actually fine.
Having said that, 18 years is long enough a time for electrolytics to suffer from ageing.
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What I meant was that the bulge is not in the cap, just in the plastic disc. Slightly bulging discs are often mistakingly taken for bulged caps.
Press down the disc. If this is easy, then it's just the plastic, if this is hard, the cap will be pushing up the disc and it has actually failed.
Press down the disc. If this is easy, then it's just the plastic, if this is hard, the cap will be pushing up the disc and it has actually failed.
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Both Digikey and Mouser's search engines allow you to choose lead spacing, diameter, height etc.
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