Roederstein 'BAKELITE' series EK capacitors - "Living Legend" OR "Looney Legacy" ...? - Page 4 - diyAudio
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Old 7th January 2013, 03:55 PM   #31
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Exclamation Batch Label - EK Series.

Hi Wrenchone.

Nice idea on the 'burn test'...
...will try !

-----------------

Labeling from Roederstein production...
...late eighties !

Cheers.


Si.
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Old 18th January 2013, 02:57 PM   #32
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Quote:
Originally Posted by Elvee View Post
Quite astonishing how user's experiences can differ.

For my part, compared to other contemporary types, I have seen very few faulty ones. As I mentioned earlier, I found some had cracked or even exploded, but it was caused by application of reverse bias.
Usually, ordinary Al caps tolerate a small percentage of reverse bias voltage during part of a cycle, but the EK do not tolerate well that kind of treatment, probably because of their hermetic construction.

There may be other factors: since they were low esr, some designers could have mistakenly thought that they were suitable for operation at high current, high temperature and high frequency. In fact, they must be 85° or perhaps 70° parts.

The equipment where I saw them were mainly professional, not consumer, conservatively designed and they weren't subjected to simultaneous stresses.

Under the same conditions, the Philips ones were awful (the ones with light blue sleeve): they simply dried up, without stress, and they even degraded under shelf storage conditions.
I cannot comment about "Japanese elco's", that is too broad.



Because the cathode connection has to be made through a thin aluminium strip welded to the bottom of the case, having a length ~150% of the cap's body.
here is my roe collection the radial electrolytics in this piccy have the same problem has the axial version..
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Old 18th January 2013, 03:03 PM   #33
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The lytics in this piccy have same problem has the axials
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Old 18th January 2013, 05:05 PM   #34
Elvee is online now Elvee  Belgium
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Quote:
Originally Posted by madtecchy View Post
The lytics in this piccy have same problem has the axials
They look like axials in (very poor) disguise. Not surprising they behave similarly.
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Old 18th January 2013, 06:43 PM   #35
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Hi,
my experience with those dull-red ROE capacitors is that they are very prone to failure after about 25 years.
They were heavily used by Bang & Olufsen and Revox since about 1970.
The first advice of all service technicians that I know, is to replace these capacitors, in whatever audio brand they are used.
About my quote about "Japanese" capacitors:
I have, and still am servicing Japanese audio gear, from 1960 on.
In my experience, the elco's very seldom fail.
I myself, I am daily using Japanese Sansui tuners and amplifiers from about 1968.
Only some dial lamps had to be replaced, not a single electronic component had to be replaced, all electrolytic capacitors are original.
These +40 years old units are performing very well, as new, and yes, I have compared them with current Japanese/Chinese production.
P.S.
In almost all consumer electronics, there is/was a plague of very bad electrolytic capacitors. They fail after about two years, especially in switching power supplies. I was disregarding these (Chinese) crap capacitors in this posting.
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Old 18th January 2013, 06:52 PM   #36
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Quote:
Originally Posted by 968driver View Post
Hi,
my experience with those dull-red ROE capacitors is that they are very prone to failure after about 25 years.
They were heavily used by Bang & Olufsen and Revox since about 1970.
The first advice of all service technicians that I know, is to replace these capacitors, in whatever audio brand they are used.
About my quote about "Japanese" capacitors:
I have, and still am servicing Japanese audio gear, from 1960 on.
In my experience, the elco's very seldom fail.
I myself, I am daily using Japanese Sansui tuners and amplifiers from about 1968.
Only some dial lamps had to be replaced, not a single electronic component had to be replaced, all electrolytic capacitors are original.
These +40 years old units are performing very well, as new, and yes, I have compared them with current Japanese/Chinese production.
P.S.
In almost all consumer electronics, there is/was a plague of very bad electrolytic capacitors. They fail after about two years, especially in switching power supplies. I was disregarding these (Chinese) crap capacitors in this posting.

It wasn't just chinese companies that got bit by this bug. Nichicon was also hit badly on several of their cap series (ones used in dell computers for example). Theirs was also exacerbated by an over filling problem that hit around the same time (too much electrolyte). The cheap chinese capacitors still fail namely because they don't use high enough purity aluminum in their caps (the copper impurities catalyze the breakdown of the electrolyte) as well as leaving out some expensive stabilizers in the electrolyte mixture.
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Old 30th January 2013, 09:31 PM   #37
mjf is online now mjf  Austria
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here are photos of an orange and grey ROE electrolytics'..........in an old echolette 150 tubeamp.
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File Type: jpg echolette150b.JPG (123.4 KB, 164 views)
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Old 30th January 2013, 10:10 PM   #38
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Ah those resistors and the metal (but open) potentiometer... old times....

Please replace the ROE stuff even if they are made by fairies and measure the lowest ESR on this planet.
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Last edited by jean-paul; 30th January 2013 at 10:13 PM.
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Old 31st January 2013, 06:04 AM   #39
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Please also replace the trimpot, the moving metal contact always breaks or is no more pressing on the carbon track.
(all Revox A-77 's are affected)
Best regards, 968driver.
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Old 23rd April 2013, 12:53 PM   #40
feds27 is offline feds27  United States
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Quote:
Originally Posted by 968driver View Post
Hi,
my experience with those dull-red ROE capacitors is that they are very prone to failure after about 25 years.
They were heavily used by Bang & Olufsen and Revox since about 1970.
The first advice of all service technicians that I know, is to replace these capacitors, in whatever audio brand they are used.
About my quote about "Japanese" capacitors:
I have, and still am servicing Japanese audio gear, from 1960 on.
In my experience, the elco's very seldom fail.
I myself, I am daily using Japanese Sansui tuners and amplifiers from about 1968.
Only some dial lamps had to be replaced, not a single electronic component had to be replaced, all electrolytic capacitors are original.
These +40 years old units are performing very well, as new, and yes, I have compared them with current Japanese/Chinese production.
P.S.
In almost all consumer electronics, there is/was a plague of very bad electrolytic capacitors. They fail after about two years, especially in switching power supplies. I was disregarding these (Chinese) crap capacitors in this posting.
Add Tandberg to the list. ROE EK used heavily by Tandberg. Would anyone know what the J2 and GPK designations stand for? My caps are ROE 220uf/16V EK J2 and ROE 470uf/16V EK GPF. I'm trying to figure out the difference between the J2 and GPK. I assume these designations tell me the tolerance/temperature range/pin spacing? I'm trying to find a data sheet for these so I can find suitable replacements. Thanks.
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Last edited by feds27; 23rd April 2013 at 12:57 PM.
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