Best electrolytics for servicing a '79 2104?

[LyseFar]

Instant death I believe. No direct witnesses, but others have heard the bang!

(I think it was @neikeel who experienced infant mortality with them...)

Well that is news to me. Never had any problems with them. I have them in 4 of my heads … in my Super Lead I have Phillips - also no problems there. I am also using Spragues in an ongoing 2204 build.
I think the Spragues are made by Vishay and should (on paper) be a quality product.
Could these experiences be a bad batch/wrong long storage maybe? Shelf life should be max two years(maybe a bit more) and they should be kept in max 75% air humidity …also no extreme temperatures.

Regarding the filter caps I also uses F+T

 

[BlueX]

This question brought more info than expected. Thanks to all that contribute!

The failures discussed could be occasional or systematic, but difficult to judge for me at least. However, I usually don't discard observations done by those who have experience.

Sprague Atom 10uF, 150V :: Sprague Atom :: Electrolytics :: Capacitors :: Passive Components :: Electronic Parts :: Banzai Music GmbH

I usually buy from this guy in Berlin.

Banzai has Vishay BC 10uF/100V. Might be sufficient for bias circuit. Valvestorm has BC 10uF/160V, but it's expensive to order just a couple of caps from US to EU.

Vishay BC-118 10uF 100V :: Vishay BC Components :: Electrolytics :: Capacitors :: Passive Components :: Electronic Parts :: Banzai Music GmbH

https://www.valvestorm.com/Products/Components/Capacitors/Electrolytic

 

[neikeel]

I’d like to say it is because of the nice metallic blue colour but not quite
I had a couple of bias caps 10uF 160v in different builds be DOA a few years ago and a 16uF preamp can. Chased my tail for ages not imagining that any might be an issue. Never had a problem with BCs/Phillips. I use 200v as they are correct size in vintage restos.
I’m sure Sprague sorted themselves out, but I have choices and exercise that choice, YMMV. Same with JJ filter caps.

 

[BlueX]

I’d like to say it is because of the nice metallic blue colour but not quite
I had a couple of bias caps 10uF 160v in different builds be DOA a few years ago and a 16uF preamp can. Chased my tail for ages not imagining that any might be an issue. Never had a problem with BCs/Phillips. I use 200v as they are correct size in vintage restos.
I’m sure Sprague sorted themselves out, but I have choices and exercise that choice, YMMV. Same with JJ filter caps.

Where do you get the 200V BC/Phillips? I haven't found any, yet.

 

[neikeel]

Look on fleabay
Guy in Netherlands, one in Poland, couple in Turkey

 

[playloud]

Where do you get the 200V BC/Phillips? I haven't found any, yet.

Looks to me that the spec that @neikeel is referring to is "200V at 125 degrees, 250V at 85"? https://www.ebay.co.uk/itm/203199131011

I think the contemporary (Vishay BC) version is MAL204213109E3. Dimensions are 30x10mm.

Then there's this 118AHT version (discontinued?) to complicate matters: https://www.ebay.co.uk/itm/314625250482

I can see why new amp designers tend to stay away from axial caps!

 

[Beryllium-9]

My '72 JMP50 has original Daly caps. It is voiced to accommodate my attack so I am afraid to touch it. My bestie for sure! I noticed a little drifting at certain instances and the filter caps crossed or tubes my mind. Replacing the filter caps would change the character of the amp so I was dreading that being the issue. I got lucky when I tested the bias caps and discovered that one was going so I replaced both with the phillips that playloud mentioned. Amp went from sounding killer to super killer! Drifting gone.

 

[dtier]

FWIW, I never install any new capacitors without leakage testing them at their rated voltage. I use a Heathkit C-3 condenser checker at present. It would be nice if you could buy them pre-tested as with tubes. You of course will know if they fail spectacularly in the amp but not necessarily if they are off spec.

I also lift cap grounds and test all caps in any older amp that I service this way. I am interested if anyone knows any additional testing methods.

 

[BlueX]

Heathkit C-3 condenser checker

Googling this takes me to radio museum, and YT video with a DIY kit. The kit could be worth looking in to. Doubt I will run into a working Heathkit C-3 soon.

Agree that there should be some method to test caps used for high voltage applications (unless ESR is sufficient). Appreciate all input here!

Heathkit C-3

Edit: https://www.antiquewireless.org/homepage/awa-capacitor-dc-leakage-tester-project/

Peak Atlas ESR Gold ESR Plus model ESR70 | Peak Electronic Design Limited