I could guess.
But instead I'll suggest you take two out of your box and do a slow reform ensuring that you reform one in the opposite polarity to the other.
You'll soon see which one leaks badly and which one reforms correctly.
Does that mean the extended warranty the salesman convinced me to pay for is worthless? 😱
I always thought that Russian/Soviet electrolytic caps are junk.
К50-6 and 16 were the reason of a lot of failures I've repaired as a kid. But it was a long time ago. Are these any good?
the caps in the picture have date-codes: 9308, meaning 1993 week 8 in the ISO marking scheme, (maybe month 8 in the Russian). Either way, the caps are electrolytic and more than 23 years old.
They will be thoroughly stale by now. Nichicon (in their applications book) reckons any electrolytic to be end-of-life at 15 years, regardless of service activity or temperature.
I would not install an old elko (for small/cheap parts, not even 5 years old) in any circumstances - you'll only have to replace it soon, for being leaky or high-ESR.
And anyway, modern electrolytics are better in most regards, and you can choose from specialised parts, including audio. The part in the photo is 470µF 6.3V; you can get these in Audio-grades like Panasonic AM for -30dB of the price of a coffee.
They will be thoroughly stale by now. Nichicon (in their applications book) reckons any electrolytic to be end-of-life at 15 years, regardless of service activity or temperature.
I would not install an old elko (for small/cheap parts, not even 5 years old) in any circumstances - you'll only have to replace it soon, for being leaky or high-ESR.
And anyway, modern electrolytics are better in most regards, and you can choose from specialised parts, including audio. The part in the photo is 470µF 6.3V; you can get these in Audio-grades like Panasonic AM for -30dB of the price of a coffee.
Before you try to measure any aluminium electrolytic you need to slowly reform it.
After being slowly reformed you can check it's leakage and if it passes that then next check the esr. If it passes that, then check the capacitance.
If it passes all three AFTER reforming, then put it to work.
After being slowly reformed you can check it's leakage and if it passes that then next check the esr. If it passes that, then check the capacitance.
If it passes all three AFTER reforming, then put it to work.
You all are right. Thank you. I use them for not important place in my product. I have not answer where is positive pole. Anyone can help me ?
There are many vintage russian oil capacitor working very well in tube amp. It seems they are not degraded after long time.
There are many vintage russian oil capacitor working very well in tube amp. It seems they are not degraded after long time.
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The POSITIVE lead is longer than the negative.
Oil capacitors are different - they can run for years without problems (but they can fail short-circuit, so I would not use them for coupling to the grid of an expensive tube).
The capacitor in the photo is electrolytic. There is no reason to use them - new ones work and sound much better, and they are very low cost.
Hi, does anyone know if the Russian 10uF 400V MBGO-2 caps have a "direction" to let the signal flow, that is how its content is wrapped and connected to the two terminals? I have not found anything on the net of these specific caps, of other Russian PIO caps on the other hand, some have a verse. Thanks!
If it's of stacked foil construction (not axial wrap but layers) there is no natural outer foil. Rectangular capacitors are usually stacked. In any case you can check sensitivity with the oscilloscope. In max vertical sensitivity you connect the probe both ways to the cap terminals and if it picks less interference with the ground crocodile to one particular terminal, you designate it as "outer foil". Better connecting that one to the lower impedance side in circuits.
Yes indeed, you are right.
I just put the container on GND.
I also have other Russian caps like the one in the picture, I checked with an oscilloscope which side is connected to the external part and which to the internal part of the "roll". When using a tube preamp output ... does the "inner" side go towards the RCA connectors?
And in use at the input of a tube preamp ... does the "inner" side go towards the grid? Did I guess at least one?
Thanks
I just put the container on GND.
I also have other Russian caps like the one in the picture, I checked with an oscilloscope which side is connected to the external part and which to the internal part of the "roll". When using a tube preamp output ... does the "inner" side go towards the RCA connectors?
And in use at the input of a tube preamp ... does the "inner" side go towards the grid? Did I guess at least one?
Thanks
That Russian MBGO-2 capacitor is metallized paper. The paper is wrapped, but not in a round roll. It is squeezed flat. It is very likely that one terminal (that is connected to the outer foil) has more capacitance to the metal can, than the other terminal (connected to the second foil layer). So the inner/outer question makes sense indeed.
I have several of this capacitors, maybe I will open one to see the internals. But it is also possible the workers don't care at the final assembling, and the outer foil is randomly connected to one or to the other terminal.
I have several of this capacitors, maybe I will open one to see the internals. But it is also possible the workers don't care at the final assembling, and the outer foil is randomly connected to one or to the other terminal.
Thanks Anyway I did a test with the oscilloscope connected to the MBGO-2 and, touching the cap, I see the same noise in the oscilloscope regardless of the "polarity" with which I connect the oscilloscope..so, for me, that cap does not have a " direction ".
Instead, the round cap in the photo above ... that is, the direction should have it.
The oscilloscope shows much more noise when I touch the cap if I put the probe tip on one of the two pins.
Instead, the round cap in the photo above ... that is, the direction should have it.
The oscilloscope shows much more noise when I touch the cap if I put the probe tip on one of the two pins.
Hi, in this capacitor in the photo, in exit from a tube preamp, which side should be put towards the output RCA? Thanks and 1000. Have a nice weekend!
The one pin you find giving less noise during the oscilloscope test when connected to the probe's ground, you orientate it towards the lower impedance side of any circuit position. For example when the capacitor is used in series for signal coupling, the source's output impedance is lower than the following stage's input impedance.
Thus the sensitive (outer foil) pin when used at a preamp's output goes opposite to the RCA i.e. towards the circuit side. If used at a power amp's input, the outer foil pin goes opposite to the circuit towards the RCA.
When used in parallel positions for decoupling, like from DC rail points to ground, the lower impedance side of the circuit is the ground itself. There goes the outer foil pin.
Thus the sensitive (outer foil) pin when used at a preamp's output goes opposite to the RCA i.e. towards the circuit side. If used at a power amp's input, the outer foil pin goes opposite to the circuit towards the RCA.
When used in parallel positions for decoupling, like from DC rail points to ground, the lower impedance side of the circuit is the ground itself. There goes the outer foil pin.