Illinois brand capacitors still bad?

[martin manning]

Thanks for this test out and post, and yes that’s over a 10% different which is a lot!

My math says over 1000% in ESR. A current data sheet from Mouser indicates IC is part of CDE, and the max ESR for 10uF 160V axial at 120 Hz is 33.157 ohms.

[Stevem]

Yes, sorry, more like ten times!
I had the morning coffee brewing but none yet to start the brain up.

[TUBEDUDE]

Were they fresh off the shelf, or after some time under voltage to form the dielectric?

[Mark]

Were they fresh off the shelf, or after some time under voltage to form the dielectric?

I bought them less than a month ago. So I’m not impressed with the performance of these caps.

[Mark]

Thanks for this test out and post, and yes that’s over a 10% different which is a lot!

My math says over 1000% in ESR. A current data sheet from Mouser indicates IC is part of CDE, and the max ESR for 10uF 160V axial at 120 Hz is 33.157 ohms.

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I will stick by my statement that I wouldn’t used the IC caps.
I have a 1972 Twin Reverb here which the dog model of Twin Reverb amps. The caps are caps we would typically replace in the amp, but these caps all have a much lower ESR figure than the IC caps. I think to replace these caps with the IC brand would be to put interior caps into an amp.

I could have it wrong, but that’s what the meter is telling me.

[martin manning]

The 10u 160V IC cap's ESR is not out of line. Check the chart that came with your Peak. Are there caps with lower ESR? Sure, and in some applications such as SMPS with high ripple current it's necessary for adequate life.

Those old Mallory's appear to be good, but if that amp is going to be a player, I'd replace them.

[TUBEDUDE]

I have one of those cheap cap checkers (different brand) and I wonder if the measured value is similar when the cap is in circuit with high.voltage on the plates.

[Mark]

I have one of those cheap cap checkers (different brand) and I wonder if the measured value is similar when the cap is in circuit with high.voltage on the plates.

The caps were measured out of circuit. I tried to make it as accurate as possible.

[Stevem]

Here’s a 1000uf 50v Rubycon that swollen and starting to leak and it still test out at only .94 ohms, unfortunately it’s only 5 years old.

[Mark]

The 10u 160V IC cap's ESR is not out of line. Check the chart that came with your Peak. Are there caps with lower ESR? Sure, and in some applications such as SMPS with high ripple current it's necessary for adequate life.

Those old Mallory's appear to be good, but if that amp is going to be a player, I'd replace them.

All the Vishay caps are the same value and voltage rating as the IC caps. The Vishay cap with the greatest ESR was 0.61 ohms. I measured a whole lot of F&T caps I have and they were giving lower ESR readings than the IC caps.

Martin you are correct that the booklet gave a higher reading as okay. The cap giving the 6.1 ohms reading wasn’t the highest value of ESR.

I put up pictures of old caps as I wondered if old vintage caps had a high ESR, if vintage caps had a high ESR then the IC caps might have been a good thing, but the ESR value of the caps was low.

I don’t know if anyone could hear the difference between between IC caps and Vishay caps, but I do want a line in the sand regarding the quality of the components I use.

I think with the competition between solid state and valve amps had intensified, I’m not prepared to give ground. I think we should be aware of the short coming of some brands of components too.

End of rant.

[Mark]

Here’s a 1000uf 50v Rubycon that swollen and starting to leak and it still test out at only .94 ohms, unfortunately it’s only 5 years old.

I have encountered caps that started spilling the dielectric and still having a low ESR. The Rubycon does look as back as one Astron caps I pulled out of my Bandmaster. I have had the same filter caps in the Bandmaster since 1997 and they are still going strong. They are Sprague caps.

[TUBEDUDE]

I have one of those cheap cap checkers (different brand) and I wonder if the measured value is similar when the cap is in circuit with high.voltage on the plates.

The caps were measured out of circuit. I tried to make it as accurate as possible.

Sorry I wasn't clear Mark. I meant after they were under high voltage to break them in first. Then out of circuit to be measured. Electrolytics need time under voltage to fully form the insulating layer. Measurements should be made after break in. Will the difference be substantial? I'll find out after I'm out of this cast, if no intrepid experimenters leap into the breach. (tendon transfer has my dominant hand deadlined for now)

[maxkracht]

I was under the impression that low voltage esr testers weren't necessarily accurate for high voltage caps. That atlas tester is putting out ~12v? I have also measured plenty of old electrolytics that have blown their guts but still test OK on an LCR meter. Sometimes the amp isn't even that noisy; maybe some intermittent stuff when the caps get too hot, vomit, then reforms. I bought a high voltage Sprague cap tester years ago but I never use the thing. Doesn't seem to be worth the time to test something you know will go bad sooner than later...

(tendon transfer has my dominant hand deadlined for now)

Hope the hand feels better soon, that doesn't sound like fun.

[Stevem]

Don’t forget with these great little testers to discharge the cap before testing.

My co worker killed is tester 3 days after he built it with a charged up 450 volt cap.

You need to confirm after discharging that there is no more voltage left in the cap then the battery that powers it.

[Mark]

I was under the impression that low voltage esr testers weren't necessarily accurate for high voltage caps. That atlas tester is putting out ~12v? I have also measured plenty of old electrolytics that have blown their guts but still test OK on an LCR meter. Sometimes the amp isn't even that noisy; maybe some intermittent stuff when the caps get too hot, vomit, then reforms. I bought a high voltage Sprague cap tester years ago but I never use the thing. Doesn't seem to be worth the time to test something you know will go bad sooner than later...

(tendon transfer has my dominant hand deadlined for now)

Hope the hand feels better soon, that doesn't sound like fun.

I haven’t heard anything about the testers not being accurate. The Sprague testers are great, I have used one in the past. Actually, I tested a Astron electro that was spewing its dielectric on the Sprague tester and it had low ESR. You just jogged my memory, I thought it was most peculiar.