Russian PIO caps. Should I use them?

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Joined 2002
#1
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.
 
#5
Wavebourn said:



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

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.
 
#6
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??
 
#7
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...........
 
#9
Wavebourn said:


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.
Click to expand...
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!!!
 
#10
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.
 
#11
Svein_B said:
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
Click to expand...
Excellent, that is a good summary!!

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

Svein.
Click to expand...
Me either. The only characters that I can understand are the numbers :xeye:
 
#13
Svein_B said:


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

Svein.
Click to expand...

This table is the result of measurement of a tangent of a degree of losses for frequencies 100 Hz, 1 KHz, and 10 KHz for different types of capacitors the author measured..

An externally hosted image should be here but it was not working when we last tested it.



In conclusion he says that measurements can't help too much to predict sonic impact. :xeye:

According to his tests, paper+foil in oil sound better then others, while Ftoroplast capacitors sound the best.
 
#17
Soviet Capacitors

Just one remark - ftoroplast mean teflon - FT and K72 capacitors are teflon caps. I can suggest improvement of the K40 -U9 capacitors. Undress it and it will sound wonderful.

Soviets made lot of fantastic components but problem is lack of information!

Regards
 
#19
My private list:

K15-4 Ceramic HV "doorknobs"
K15-5 Ceramic HV Disc

K31 Silver Mica "kidney bean" style cap

K40P-2B Paper in Oil, aluminium foil, 5% tol.
K40U-9V Paper In Oil , aluminium foil, Silver body, 10% tol. (also called K40Y-9)

K41-1A PIO, High Voltage "Pulse" caps

K42U-2 metalized paper PIO, green painted body (K75 are better)

K50 Aluminum Electrolytic

K70 Polystyrol

K71-7V Polystyrol "High Tolerance" 1% or 2% tol.

K72P-6 Teflon Dielectric 5% tol. (see example below)

K73-14 PETP High Voltage
K73-15 PETP / Dry Mylar
K73-16 PETP / Dry mylar
K73-17 PETP
K73P-4 "tub " style AC capacitors (may be paper or mylar, still TBD).

K74 PETP HV caps

K75-10 PIO, Green body (these are the prime quality PIO)
K75-15 PIO, High Voltage "tub"
K75-17 PIO High Voltage "tub"
K75-24 PIO Green body tubular (see example below)
K75-28 PIO High Voltage "tub"

K76 Laquer film

K77 PolyCarbonate film

K78 PolyPropylen film

BMT-2 Paper In Oil

FGT High Voltage Teflon Dielectric, Ceramic body (almost beer can size)

KBG, OKBG PIO (no, this isn't the KGB, they're a different entity altogether)

KBI HV "doorknob" RF / Transmitting cap

KSO Silver-Mica "precision" caps

SGM3-A, SGM3-B Silver-Mica "precision" caps (in oil?)

MBG, OMBG-2, MGBO-1, -2, MBGP-2, -3 Metallized Paper-Aluminum "tub" AC caps

MBGCh Metallized Paper pulse capacitors
 
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