Would you install a N.O.S. multi-section can cap (over 10 yrs. old/

RE: Would you install a N.O.S. multi-section can cap (over 10 yrs. old/, posted on January 14, 2021 at 17:52:47
Tre' Industry Professional Posts: 17294 Location: So. Cal. Joined: February 9, 2002	After reforming and testing, yes. Tre' Have Fun and Enjoy the Music "Still Working the Problem"

RE: Would you install a N.O.S. multi-section can cap (over 10 yrs. old/, posted on January 14, 2021 at 21:11:38
Coner Audiophile Posts: 3703 Location: S.W. Washington state, USA Joined: November 17, 2001	Thanks Tre'. I'll check date codes, but how old is the point which you'd not use them?. I suspect they're at least 20 y/o.

RE: Would you install a N.O.S. multi-section can cap (over 10 yrs. old/, posted on January 14, 2021 at 22:15:36
Eli Duttman Audiophile Posts: 10455 Location: Monroe Township, NJ Joined: March 31, 2000	Tre' gave you a plan of action. The $64 question is whether or not individual seals have held. Reform and test each individual section. High ESR readings indicate drying out has occurred. Eli D.

ESR, posted on January 15, 2021 at 01:03:07
Triode_Kingdom Audiophile Posts: 10044 Location: Central Texas Joined: September 24, 2006	"High ESR readings indicate drying out has occurred." This can't be overstated. I wouldn't even think about using 20-year-old caps without testing them with an ESR meter first.

Are they temperature rated?, posted on January 15, 2021 at 05:05:41

1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007

I agree with Tre' and Eli that testing them for ESR and reforming them is critical.

I'd also want to know (if possible) what their temperature rating is. I have a 20+ year old NOS (made in Mexico) Mallory, for example, with no temperature rating listed. I've seen some new production multi-section cans rated as low as 55 C (131 F), which I wouldn't be comfortable using in the close quarters of a Dynaco tube amp, for example, where they're butted up close to the power transformer. Caps heat, not only from the external heat radiation they're subject to, but also internally, due to ripple, from what I've read. Therefore, the first cap in a C, L, C etc may be under more thermal stress.

If I was restoring a vintage amp where originality mattered, I'd use the cans which tested good. But would I use them in a new build or rebuild, where appearance or resale value didn't matter, just to save a few bucks? No.

RE: Would you install a N.O.S. multi-section can cap (over 10 yrs. old/, posted on January 15, 2021 at 05:59:05
kyle Audiophile Posts: 1839 Location: London Ontario Joined: September 29, 1999	When you consider the cost of the other components in the average tube amp, does saving $40 on a 4 section cap make sense? If they're 2 section caps, JJ and F&T have versions for $10 to $15 that work well.

How high?, posted on January 15, 2021 at 09:26:56

Lew
Audiophile

Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000

How for over spec would the capacitor have to be for you to conclude it is not salvageable? Or would it be prudent to try to re-form it and then re-check ESR? If at that point ESR is still high, perhaps then you would discard the capacitor as dried out?

This thread reminds me I have a container full of ELNA Cerafine capacitors, 350V and higher rated, that are probably close to 20 years old and have never been used. I periodically think I should toss them, but I cannot bear to do it. I bought them from M Percy when he was selling out his stock.

RE: How high?, posted on January 15, 2021 at 10:29:06

Triode_Kingdom
Audiophile

Posts: 10044
Location: Central Texas
Joined: September 24, 2006

I should pre-qualify my comments by acknowledging that I don't own an ESR meter. I only use late production electrolytic caps, so I rely on the specified characteristics. That aside, ESR meters usually come with graphs that show generally acceptable windows for ESR based on capacitance. I would use those as a guide, unless it's a fairly new capacitor with a published specification that can be used to cull the bas ones. No, I wouldn't try to reform a capacitor with high ESR. That would indicate to me that the part has dried out.

Thanks for that chart, T_K ;-) ....NT, posted on January 15, 2021 at 11:20:29
Coner Audiophile Posts: 3703 Location: S.W. Washington state, USA Joined: November 17, 2001	nt

RE: Would you install a N.O.S. multi-section can cap (over 10 yrs. old/, posted on January 15, 2021 at 16:29:52
Coner Audiophile Posts: 3703 Location: S.W. Washington state, USA Joined: November 17, 2001	Right, would not do it on a nice audio amp, mostly referring to older guitar heads or combo amps. Would not risk burning up a tranny...good point.

RE: Would you install a N.O.S. multi-section can cap (over 10 yrs. old/, posted on January 16, 2021 at 06:11:12

FlaCharlie
Audiophile

Posts: 940
Location: Gville, FL
Joined: June 1, 2003

I've never installed NOS lytics in anything but I've restored lots of vintage gear with the original cans. At first, I routinely disconnected the cans and mounted new individual caps underneath. Then I got an ESR meter.

That ESR meter was a cheapy from MAT Electronics. It has an analog meter and I never totally trusted its readings in absolute terms, but it's still very useful.

After bringing it up very slowly on a variac, I test the old cap. If its capacitance level is still in spec I do an ESR test and compare it to a new cap. I totally ignore the actual ESR reading. I'm only interested in how it compares to the high quality new cap that I would use as a replacement.

I don't replace nearly as many caps as a result as there is often very little difference in ESR. To my surprise, I've actually had some old cans that test at lower ESR than new caps.

The caps that I almost always find to be bad are not in cans. They're the individual low voltage ones typically used as cathode bypasses. I don't even bother to test them anymore, I just replace them.

RE: Would you install a N.O.S. multi-section can cap (over 10 yrs. old/, posted on January 16, 2021 at 08:49:47
Spantou Audiophile Posts: 115 Location: Central Illinois Joined: October 5, 2016	Great experienced-based information. Thank you!

RE: How high?, posted on January 16, 2021 at 12:18:56
Lew Audiophile Posts: 10911 Location: Bethesda, Maryland Joined: December 11, 2000	Thanks for that bit about not reforming a cap with high ESR. Sadly, that is the state of most of my ELNA Cerafines. Yet I cannot bear to throw them away; maybe I am hoping for a resurrection. I do own a Sencore L75 capacitance/inductance meter, and it tells me my ELNAs are toast, by the high ESR criterion.

RE: Would you install a N.O.S. multi-section can cap (over 10 yrs. old/, posted on January 16, 2021 at 13:22:42
deathtube 667	When DC Link and other low ESR pulse rated caps are readily available, why use NOS? NOS are OK for restoring vintage console amps but not for "hi-fi" applications.

RE: Would you install a N.O.S. multi-section can cap (over 10 yrs. old/, posted on January 16, 2021 at 13:28:14
rivervalley817	some people have parts bins that go waaaay back DT that, and they're cheap sum britches too! be well,

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Would you install a N.O.S. multi-section can cap (over 10 yrs. old/

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