Jump to content

Sign in to follow this  
Zaphod Beeblebrox

Jamicon capacitors

Recommended Posts

Jamicon electrolytic caps have been mentioned a few times in this forum. In the past few months, I've had two different amplifiers, from the same manufacturer land on my bench. Both use/d Jamicon caps. Now, the caps were bad enough, but the problems were significantly compounded by other factors. First, we start with amplifier #1:

 

Problems noted:

* Jamicon caps are not in the top tier of cap manufacturers. They are decidedly below average in my experience.

* Rail Voltage was 62 Volts DC (with a precise 240VAC supplied via a Variac™).

* Rated capacitor Voltage was 63 Volts DC.

* Capacitor temperature rating was 85 degrees C.

* Heat sinking consists of horizontal fins, rather than vertical. Thus, convection cooling was almost non-existent and radiation was the only method available. Heat is thus radiated inwards as well as out. 

* Leaking capacitor gunk™ (the trade marked term for the fluid inside electrolytic caps) has damaged the printed circuit board (PCB) and thus caused the output stage to fail. 

 

Solutions:

* Fit decent quality caps. In this case, Nichicons

* Fit higher Voltage caps. In this case, 80 Volts.

* It would have been preferable to fit 105 degree C caps, but these were not available at the time of service.

* Fit larger caps, for an improvement in sound quality.

 

Photos:

1) 8 main filter caps. 4 are completely destroyed.

2) Leaked gunk™ on the PCB and the resultant damage to the output stage.

3) Measurements performed on one of the caps that appeared to be OK. Note the ESR value.

4) Measurement of a good quality cap. Note the ESR value.

5) New caps fitted.

6) New caps fitted.

 

Next up, amplifier #2.

Share this post


Link to post
Share on other sites

Jamicon electrolytic caps have been mentioned a few times in this forum. In the past few months, I've had two different amplifiers, from the same manufacturer land on my bench. Both use/d Jamicon caps. Now, the caps were bad enough, but the problems were significantly compounded by other factors. First, we start with amplifier #1:

 

Problems noted:

* Jamicon caps are not in the top tier of cap manufacturers. They are decidedly below average in my experience.

* Rail Voltage was 62 Volts DC (with a precise 240VAC supplied via a Variac™).

* Rated capacitor Voltage was 63 Volts DC.

* Capacitor temperature rating was 85 degrees C.

* Heat sinking consists of horizontal fins, rather than vertical. Thus, convection cooling was almost non-existent and radiation was the only method available. Heat is thus radiated inwards as well as out. 

* Leaking capacitor gunk™ (the trade marked term for the fluid inside electrolytic caps) has damaged the printed circuit board (PCB). 

 

Solutions:

* Fit decent quality caps. In this case, Nichicons

* Fit higher Voltage caps. In this case, 80 Volts.

* It would have been preferable to fit 105 degree C caps, but these were not available at the time of service.

* Fit larger caps, for an improvement in sound quality.

 

Photos:

1) 8 main filter caps. 4 are completely destroyed.

2) Leaked gunk™ on the PCB. 

3) Measurements performed on one of the caps that appeared to be OK. Note the ESR value.

4) Measurement of a good quality cap. Note the ESR value.

5) New caps fitted.

6) New caps fitted.

 

Next up, amplifier #2.

1.JPG

2.JPG

3.JPG

3.JPG

4.JPG

4.JPG

5.JPG

6.JPG

Edited by Zaphod Beeblebrox
Failed photo upload.

Share this post


Link to post
Share on other sites

Amplifier #2:

 

Problems noted:

 

* Jamicon caps. AGAIN!

* Rail Voltage was 76 Volts DC (with a precise 240VAC supplied)

* Capacitor Voltage rating was 80 Volts DC (minimal overhead).

* Capacitor temperature rating was 85 degrees C.

* Horizontal heat sink fins.

* Leaking capacitor gunk™ damaged the PCB AND resulted in the destruction of one output stage. 

 

Solutions:

 

* Fit decent quality capacitors. In this case, Nichicons.

* Fit higher Voltage rated caps. In this case, 100 Volts DC.

* Fit higher temperature rated caps. In this case, 105 degrees C rated.

 

Photos:

 

A_1) Two visibly faulty caps.

A_2) Measurement of a visibly OK cap. Note the ESR figure.

A_3) Damage to the PCB and output stage from leaking capacitor gunk™.

A_4) Measurement of the replacement caps. Note the ESR figure.

 

 

Moral: Be very wary of Jamicon caps. Be very wary of caps that are fitted to hot running products, where proper attention to cooling of those caps is ignored. Be very wary of caps that are operated close to their maximum Voltage ratings.

A_1.JPG

A_2.JPG

A_3.JPG

A_4.JPG

Share this post


Link to post
Share on other sites

Ouch! That's disappointing. Zaphod, how old were these amps please?

Share this post


Link to post
Share on other sites


I don't know. Amplifier #2 dates from around 2008 I think. Amplifier #1 would probably be a similar vintage, but I can't say for certain. 

Share this post


Link to post
Share on other sites

I know you would like people to come use your service to change out capacitors, and am sure you do this a lot. However I know quite a few makers. reputable ones...still in business and have been for many years decades infact using these.

 

and I also personally own some gear thats 20+ years old going quite fine thanks you very much. so while this is something you see as some public service announcement, I am also going to counter it by saying....while you think it necessary for people to be bringing to you to fit nichicons and such sorry to advise but there are a lot of these amplifiers going along quite well many years in service thankyou very.

 

just like anything equipment can fail and does in many cases, it doesnt mean things have to be changed out willy nilly ! 

 

I certainly have absolutely no intent of doing any such thing and neither would i personally suggest  it to anyone who might have something working perfectly well as the manufacturer intended.

 

and ps while talking about positioning of cooling fins. why dont you talk about makers particularly lot of japanese ones that put their heat dissipating fins....inside the amplifier casing...so all the heat generated can dissipate inside the case and have the amp nicely slow cook from the inside ? why not mention that hey ? 

 

oh and then there are ones that use fans and then on top of it put filters in front...and ofcourse we do know fans are mechanical items that can and do fail...and filters also can and do block up...also leading to amps that eventually fail. am sure youve come across plenty that have. how about those :) am sure thats a contributing factor to heat build up inside a amp and eventual failure ! 

Share this post


Link to post
Share on other sites

My warning was not a personal advertisement. It was simply a warning about poorly chosen and poorly used components in some products. I was asked some time ago to post investigations in this part of the forum. I have been searching for a good reason to do so. I believe the issue of Jamicon capacitors is a good one. Most techs in this business will attest to the (lack of) quality of Jamicon caps. 

 

Was there a problem with the photos that showed the damage caused by these capacitors? 

Edited by Zaphod Beeblebrox

Share this post


Link to post
Share on other sites
41 minutes ago, Zaphod Beeblebrox said:

I don't know. Amplifier #2 dates from around 2008 I think. Amplifier #1 would probably be a similar vintage, but I can't say for certain. 

 

That's disappointing for a premium brand (I think we all know which brand is being discussed).

Share this post


Link to post
Share on other sites


It's not just Jamicon that do this  I've seen other brands such as Nichicon and Elna do the same, and they were operating well under the operating voltage of what the specs are.   Don't have photos because I saw these almost over a decade ago when I was working for 2 different organisations.  I had a Rubycon in a Sharp copier blow up in my face as I was getting a voltage reading and stunk the whole warehouse out.   I see it less now because the manufacturer I work for now have some very reliable Electronics and we rarely have any issues.

The other onus is on the brand of products that go on the cheap, and Roger Sanders is no different.   He was using 100V / 10.000uf Jamicon caps 85C in a Sanders Magtech early in the peace and it's caused him enormous grief.  He is now using 120V 8200uf 85C in all his current Magtech and I'm on the constant watch for leaks on the one I have,  I'm just lucky that he provides a lifetime warranty and in one case on a different thread he didn't asked for proof of purchase all questioned how the amplifier was used and send out 8X 120V 8200uf and 2 amplifier modules brand new to a member here @realysm42 who didn't have any tools to fit the caps.

 

 

So what's your problem @Zaphod Beeblebrox  Jamicon caps are the best, they pay your bills!   :D:thumb::na:

 

Share this post


Link to post
Share on other sites

i can see one of the pics has internal fins...so how were these amps used ? how often do we see on this forum people with gear all stacked on top of each other and cooling and ventilation holes being in. how do we know these didnt cook from the inside over the some 8-9 years of its life ? 

 

I've owned Harman kardon amps for instance huge fins all internal... gee unless you had those sitting well ventilated and nothing on top they would cook from the inside. given how hot they ran ! 

Share this post


Link to post
Share on other sites
Just now, :) al said:

i can see one of the pics has internal fins...so how were these amps used ? how often do we see on this forum people with gear all stacked on top of each other and cooling and ventilation holes being in. how do we know these didnt cook from the inside over the some 8-9 years of its life ? 

 

Excellent point. I did advise the client to ensure adequate air flow. However, the major part of the problem, IMO, was due to the marginal Voltage ratings of the caps chosen. 

 

Just now, :) al said:

 

I've owned Harman kardon amps for instance huge fins all internal... gee unless you had those sitting well ventilated and nothing on top they would cook from the inside. given how hot they ran ! 

 

Indeed. Old HK amps certainly have reputation for this. In fact, their driver transistors run so warm that solder joints fracture after a decade or so. They can be frustrating to service, due to the number of dry solder joints. That said, I don't see many late model HK amps, so this issue may have been addressed. 

Share this post


Link to post
Share on other sites
15 minutes ago, Quark said:

 

That's disappointing for a premium brand (I think we all know which brand is being discussed).

 

Brand bashing was not my intent (unless you count Jamicon). I really don't like the damned things. I have a bag of 200 (less a bunch that were used) small Jamicon caps I purchased a few years ago. I discovered that they were dodgy, after I had fitted them to clients' products. I then had to recall the dozen or so products and replace the caps with Panasonics. It cost me dearly. I have never used Jamicons since. I keep the bag to remind me that saving a few cents can result in much larger costs further down the line. 

 

That said, Andy's comments are bang-on. ANY cap operated close to or beyond it's limits is likely to experience premature failure. 

Edited by Zaphod Beeblebrox

Share this post


Link to post
Share on other sites


30 minutes ago, Zaphod Beeblebrox said:

 

Brand bashing was not my intent (unless you count Jamicon). I really don't like the damned things. I have a bag of 200 (less a bunch that were used) small Jamicon caps I purchased a few years ago. I discovered that they were dodgy, after I had fitted them to clients' products. 

 

 

If you still have them bin them or send them to North Korea.....:P 

there not good for your health or your stress level!   

 

 

Share this post


Link to post
Share on other sites
4 minutes ago, Addicted to music said:

 

 

If you still have them bin them or send them to North Korea.....:P 

there not good for your health or your stress level!   

 

 

 

Yeah, I'll chuck them one day. For the time being, I use them to shame the manufacturer and supplier. FWIW: This batch of caps exhibited a 30% failure rate. Despite having used thousands of Panasonics in the intervening period, I've experienced perhaps one or two failures. Way, WAY less than 1%. 

Share this post


Link to post
Share on other sites

The voltage ratings barely above rail voltage is a bit of a worry.

Share this post


Link to post
Share on other sites
12 minutes ago, Zaphod Beeblebrox said:

 

Yeah, I'll chuck them one day. For the time being, I use them to shame the manufacturer and supplier. FWIW: This batch of caps exhibited a 30% failure rate. Despite having used thousands of Panasonics in the intervening period, I've experienced perhaps one or two failures. Way, WAY less than 1%. 

 

I love those Panasonic caps, I have replaced the Sanders Preamp with Panasonic TP 5100uf/25V and SQ changed.....however I didn't do a DBT!   

They are very nice caps but are only in small values.

 

Share this post


Link to post
Share on other sites


It seems hard to believe a good brand hifi product would use lower quality capacitors and be so close to their voltages.

It really seems penny pinching at the extreme.

No excuse to not fit quality Japanese made caps at the start (with some headroom), charge a few dollars more and then they can also advertise and make a thing of it that they are using higher quality caps/parts.

How much extra would it actually add to the price in manufacture. Is it really that much, to make them use lower quality parts?

If it is a lot of money, there could be a reason why they are so cheap.

Edited by rocky500

Share this post


Link to post
Share on other sites

I cannot fathom the interpretation of this post as an 'ad' or 'touting'.  The initial post is entirely reasonable, technically literate and fair opinion.  I have also had similar experience with the brand mentioned; and some others that I won't mention for fear of being branded a 'brand basher'.

 

Simple message; use quality caps, with an appropriate safety margin for both voltage and temperature, especially in the Australian environment with it's somewhat variable mains and weather.  Simples...  

 

:thumb:

Share this post


Link to post
Share on other sites
21 minutes ago, Gruffnutz said:

I cannot fathom the interpretation of this post as an 'ad' or 'touting'.  The initial post is entirely reasonable, technically literate and fair opinion.  I have also had similar experience with the brand mentioned; and some others that I won't mention for fear of being branded a 'brand basher'.

 

Simple message; use quality caps, with an appropriate safety margin for both voltage and temperature, especially in the Australian environment with it's somewhat variable mains and weather.  Simples...  

 

:thumb:

 

 

Absolutely agree 100%  - sharing such information is very useful, especially for those who have a technical interest in such things.

Share this post


Link to post
Share on other sites
Guest

@zaph, thanks for posting, nice cap tester BTW :)

Share this post


Link to post
Share on other sites
20 minutes ago, 125dBmonster said:

@zaph, thanks for posting, nice cap tester BTW :)

 

 

I know, I now have one of those, awesome toy.:thumb:

IMG_1028.JPG

IMG_1027.JPG

Share this post


Link to post
Share on other sites


Zaph, you should know that when running a cap so close to it's voltage limits, all it takes is the mains voltage to spike or go up a few percent and the DC rail goes above the capacitors rated voltage.

I dont think in this case it's Jamicon's fault.

I've found occasions where Jamicon's capacitors are the best sounding when compared to other brands in a particular circuit.

Sent from my Moto G (4) using Tapatalk

Share this post


Link to post
Share on other sites

Here's one from my bench today. This is what happens when the machine puts the capacitor in backwards0b0cf6ad90137e64c44ec996fa99f381.jpg

Sent from my Moto G (4) using Tapatalk

Share this post


Link to post
Share on other sites
1 hour ago, eltech said:


Zaph, you should know that when running a cap so close to it's voltage limits, all it takes is the mains voltage to spike or go up a few percent and the DC rail goes above the capacitors rated voltage.

I dont think in this case it's Jamicon's fault.

I've found occasions where Jamicon's capacitors are the best sounding when compared to other brands in a particular circuit.

Sent from my Moto G (4) using Tapatalk
 

 

Absolutely correct. Poor design, combined with poor component choice (marginal Voltage rating), leads to a bad result. That said, I have Jamicon caps which are brand new and clearly rubbish. I'll post some more photos later. 

Share this post


Link to post
Share on other sites
 
Absolutely correct. Poor design, combined with poor component choice (marginal Voltage rating), leads to a bad result. That said, I have Jamicon caps which are brand new and clearly rubbish. I'll post some more photos later. 


Definitely let us know which model, date code, and why they don't meet spec. I also have an ESR meter, a very handy tool!

Sent from my Moto G (4) using Tapatalk

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

  • Classifieds Statistics


    Currently Active Ads

    Total Sales (Since 2018)

    Total Sales Value (Last 14 Days)

    Total Ads Value (Since March 2020)
  • Recently Browsing   0 members

    No registered users viewing this page.


×
×
  • Create New...