Rubycon caps identification

[Karagjozi_XIII]

Hi,

I did find some nice stash of pretty old Rubycon capacitors, type is unknown to me. Certain quantity I bought almost 20 years ago, they look as normal electrolytic but I was told that those are bipolar non-electrolytic. Any idea what type/dielectric is in question? Are they any good for audio application in valve amplifiers, or shall I discard them as worthless ancient junk? Any answer will be highly appreciated.
Cheers, Mladen

[RukyCon]

Re: Rubycon caps identification

The arrows on the capacitor suggests that this is not a bipolar capacitor. As for the type of capacitor, i would say it's a electrolytic based off of it's shape and the arrows pointing at one of the legs (most likely the negative leg.)

Are they any good for audio application in valve amplifiers, or shall I discard them as worthless ancient junk?

That's hard to say, for one thing do the caps even work? If not then you're better off getting rid of them and buying new. If so then the next question would be should you use them. A lot of people would tell you to get brand new capacitors because you don't know how long those old capacitors last if you did use them, because as a capacitor ages the chemistry of the electrolyte can change which can cause the capacitor to fail prematurely (but that's not always the case.) you may also want to reform the capacitors before use. (There's a thread you can read about how to Recondition (reform) electrolytic capacitors somewhere on this site)

I hope something i said will help you.

[Karagjozi_XIII]

Re: Rubycon caps identification

Thanks ruky con,
This is exactly what I thought, regarding axial alu-can type package.
I will further investigate the possibility of reconditioning old elcos, since my stash include a lot of old ELNA, FRAKO, Nichicon and Matsushita's. These days I can't find nothing better than Samwha in local shops, and after reading posts on this forum, for sure I will stick to good originals.

[Behemot]

Re: Rubycon caps identification

The arrows on the capacitor suggests that this is not a bipolar capacitor.

Not really. Could just describe the best orientation. Although non-polarised caps can accept voltage in both ways, even those have a better orientation with less noise (or something) for audio circuits. Old caps had that, newer ones don't. Most ppl do not even know that, these nuances are what differentiate the best audio gear from the rest

[stj]

Re: Rubycon caps identification

there is a vid on youtube showing how to determine the polarity of film caps at carson's lab!!

[RukyCon]

Re: Rubycon caps identification

I'm pretty sure the Rubycon capacitors he has are electrolytic capacitors. (I could be wrong but i don't think that's likely in this case)

[stj]

Re: Rubycon caps identification

600v???

[RukyCon]

Re: Rubycon caps identification

600v???

I have a really old 500v rated electrolytic capacitor.

[LLLlllou]

Re: Rubycon caps identification

Hi,

I did find some nice stash of pretty old Rubycon capacitors, type is unknown to me. Certain quantity I bought almost 20 years ago, they look as normal electrolytic but I was told that those are bipolar non-electrolytic. Any idea what type/dielectric is in question?

Rip one open with a pair of wire cutters.

Are they any good for audio application in valve amplifiers, or shall I discard them as worthless ancient junk? Any answer will be highly appreciated.
Cheers, Mladen

Assuming they are still within their rated specs, I'd use them. If they're paper dielectric, they would leak current like a resister. Apply 600VDC across it and measure the current through it.

[kc8adu]

Re: Rubycon caps identification

those are probably paper in oil.
very old.

[stj]

Re: Rubycon caps identification

wouldnt the oil be pcb's??

[kc8adu]

Re: Rubycon caps identification

possibly.
but like many pcb caps its nothing to worry about.
modern china shit equipment is far more likely to harm you.

wouldnt the oil be pcb's??

[Behemot]

Re: Rubycon caps identification

Yep, unless you burn and breath it or lick it there's nothing to worry about.

[coreAngel]

Re: Rubycon caps identification

Sorry for the late reply this is a Rubycon Audio (paper) capacitors they are vintage usually sold as NOS (new old stock) and are really rare to find.
and are usually used in single ended audio triode power amps.