Russian PIO caps. Should I use them?

[G]

I have some capacitors that are supposedly PIO. They are silver. about 1.5"x1.5"x1.5" and have two solder terminals on "top". They are 1uF/750 volts. Are these ringing a bell with anyone? I've had them for about 3-4 years and I would like to use them for signal caps. Not sure if I should though.

[Wavebourn]

How are they marked: something like МГБ or К70-4 ?

[G]

Originally posted by Wavebourn
How are they marked: something like  or 70-4 ?

They are marked МГБ4-1. Is that good?

[Wavebourn]

Originally posted by G



They are marked 4-1. Is that good?

Metalized film on a paper, hermetically sealed. Yes, it is good, but paper and foil are better.

[G]

Originally posted by Wavebourn



Metalized film on a paper, hermetically sealed. Yes, it is good, but paper and foil are better.

My bad. They are marked МБГ4-1. I doubt that makes a difference though. Will they sound better than a Mundorf Supreme film cap? If not I won't bother.

[soundbrigade]

Polypropylene and metalfoil - hard sintered makes the best caps.
If you have those PIOs at hand - use them.
You should also know that it is common practice that many so called Audio Quyality caps are standard caps with fancy names and a not so fancy price tag. So propably your Russian caps are "better" than the Mundorf. Whatever "better" means??

[JandG]

All I can say is I have a drawer full of the fancy caps & now use russian k-40's in all my DHT amps & pre's. Why..? beacuase they are noticably superiour & a bonus is they are far & away cheaper. especially in bulk...........

[Wavebourn]

Originally posted by G


My bad. They are marked 4-1. I doubt that makes a difference though. Will they sound better than a Mundorf Supreme film cap? If not I won't bother.

I mean paper and foil is better. Metalized paper anyway is good. Though I use K73-16 caps and MLT resistors in my amps, they are great.

[pchw]

Originally posted by Wavebourn


I mean paper and foil is better. Metalized paper anyway is good. Though I use K73-16 caps and MLT resistors in my amps, they are great.

Sorry for OT is little, just want to learn a little more about the Russian caps.
Is there any English site that explain the Russian caps? If not, can you help me understanding a few common ones found in ebay?
1. Are the last 2 digits of the K73-XX used to indicate the form factor such as radial or axial only?
2. There are various K40 and K42 types of PIO, e.g. K40Y9, K42Y2. Is there any rule of thumb to indicate one is superior to the other?
3. Then we have the FT1, FT2, and FT3 teflon caps. The higher number is more expensive, and I assume that implies better :-) But why?

Thanks!!!

[Svein_B]

Here is a short summary I copied from somewhere:

K31, SSG, SGM, KSO - mica, some types with silver - good
K40 - PIO - very good
MBGxx, KBG-xx, OMBG - PIO
K42, MBM, BM-x - paper (w/o oil ??)
K70, K71 - Polystyren ("polystirol") - good
K72, FT - teflon ("ftoroplast") - THE BEST
K73 - Polythelene Teraphthalate film ("lavsan") - poor
K75 - combined Paper+Film (Polythelene Teraphthalate??, with or w/o oil??)
K76 - Laquer film
K78 - Polypropilen


Here is an article in Russian (I can not read it!)
http://www.magictubes.ru/ves/kondens.htm

Svein.