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Russian MBGO Paper In Oil Caps


Racer  X

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I think we all wish he was giving them away for free lol

 

I don't want to divulge too much info but we have been messaging and I recommended those to him as an affordable way to try paper and oil capacitors. I am certain he will come back in and have a full review of them but from what I gathered he was pretty blown away by the improvement they made compared to Solen polypropylene capacitors that were in there.

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And I'm very happy with the change.  I originally came to lurk the forum for recapping my Heresys.  Quickly got sucked in and now the Heresy is no longer recognizable.  As for the caps, I initially went with the economical Solens, all the choices were bewildering.  Did not notice much change from the 2 uf square black caps.  Happy, but reading about all the caps, maybe things could be better.  Was gathering my resources for some fancier caps, when Captain Beefheart provided a timely tip to the Russian NOS PIO caps on ebay, there are a few different sellers of the military surplus caps.  They are priced even more economically than the Solens, but the shipping is of course more expensive.  But ten days later they arrived on the doorstep on the earliest expected delivery date.

 

I bought a large assortment so I could build every variation of the Heritage crossovers, and the ALK Universal.

My first build is similar to the swamped type E used before with the Solens, but with the tweeter cap directly to the input instead via the T2A autoformer.

 

Compared to the Solens, the Russian PIO caps are louder, more lively, and dynamic.  The sound is fuller, has more body.  I'm able to listen at louder volume.  Still adjusting to the sound, and hope to tweak the voicing, balance as days go on, but extremely happy.  I am now enjoying the music rather than listening for how it sounds, it is a more natural presentation, romantic, and reminiscent of the sound of my LaScalas new in 1981 which had the large PIO motor run caps on a Type AA.  My Jones for fancy boutique caps has been satiated for now.  Best part is these caps are even cheaper in price than the Solens.  Highly recommended.

 

Big thanks to @captainbeefheart  and also to @Crankysoldermeister for his encouragement and helpful suggestion to forgo the woofer cap, that was also an easy noticeable change for the better.

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Your happiness sounds very true. I am short before to take the same path after my first try with Polyester types which are electrically correct but the PIOs seem to sound much nicer. This Russian PIOs will beat every boutique cap.

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24 minutes ago, KT88 said:

This Russian PIOs will beat every boutique cap.

 

I have found this statement to be true in my experience.

 

Just imagine if Jensen or any of these other boutique capacitor companies were to manufacture these types of Russian Capacitors to the same exact construction and specifications they would be VERY expensive for them to produce. We just happen to be fortunate enough to have quality surplus Communist military electronic components be sold off to the public.

 

You get a lot for very little money it's amazing. It's also nice many have mounting ears making fastening them to the crossover board very easy.

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15 hours ago, Racer X said:

for his encouragement and helpful suggestion to forgo the woofer cap

 

I do not remember exactly what I said, but I hope it included changing the 4mH to a 2.5mH, and using the polarity of the Type E network.

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I've been using the russian polystyrene gold caps and the maybe oil green caps. The quality is amazing metal cans glass seals.

 

 

Here is a guide to the numbers:

 

K15-4 Ceramic HV "doorknobs"
K15-5 Ceramic HV Disc
K31 Silver Mica "kidney bean" style cap
K40P-2B Paper in Oil, 5% tol.
K40U-9V Paper In Oil , Silver body, 10% tol.
K41-1A PIO, High Voltage "Pulse" caps
K42U-2 PIO, green painted body (K75 are better)
K50 Aluminum Electrrolytic
K71-7V Polystyrol "High Tolerance" 1% or 2% tol.
K71-4 Polystyrene
K72P-6 Teflon Dielectric 5% tol. (see example below)
K73-14 PETP High Voltage
K73-15 PETP / Dry Mylar
K73-16 PETP / Dry mylar
K73P-4 "tub " style AC capacitors (may be paper or mylar, still TBD)
K74 HV caps

K75 Polyprop In Oil
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"
BMT-2 Paper In Oil
*** High Voltage Teflon Dielectric, Ceramic body (almost beer can size)
FT-1 Teflon Military Grade glass sealed, aluminum body (smallest)
FT-2 Teflon Military Grade glass sealed, aluminum body
FT-3 Teflon Military Grade glass sealed, aluminum body (largest)
KBG PIO (no, this isn't the KGB, they're a different entity altogether) Capacitors KBG-MN (КБГ-МН) are:

-    K (К) - aluminum foil;
-    B (Б) - paper insulation;
-    G (Г) - airtight
-    M (М) - metal casing
-    N (Н) - a normal rectangular Corps filled with oil.

KBI HV "doorknob" RF / Transmitting cap KSO Silver-Mica "precision" caps
MBG Paper-Aluminum "tub" AC caps

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17 hours ago, captainbeefheart said:

 

I have found this statement to be true in my experience.

 

Just imagine if Jensen or any of these other boutique capacitor companies were to manufacture these types of Russian Capacitors to the same exact construction and specifications they would be VERY expensive for them to produce. We just happen to be fortunate enough to have quality surplus Communist military electronic components be sold off to the public.

 

You get a lot for very little money it's amazing. It's also nice many have mounting ears making fastening them to the crossover board very easy.

Do you think ESR will be high in these old(er) surplus caps or an issue being used decades later for audio purposes?

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Just now, Curious_George said:

Do you think ESR will be high in these old(er) surplus caps or an issue being used decades later for audio purposes?

 

I had the polystyrene and green metal can glass end seals tested and they were great. The date codes are from the 80's.

 

 

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2 hours ago, Curious_George said:

Do you think ESR will be high in these old(er) surplus caps or an issue being used decades later for audio purposes?

 

No not at all, well not that I have measured anyway.

 

Audible testing confirms this, to quote RacerX

 

"Compared to the Solens, the Russian PIO caps are louder, more lively, and dynamic.  The sound is fuller, has more body."

 

If ESR was high he would have losses especially through the tweeter, it would sound dull and dark, like a blanket covering the speakers. It's the opposite when using these, the sound opens up, cleaner, crisper without fatigue. They just work very well in these speakers.

 

 

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1 hour ago, captainbeefheart said:

 

No not at all, well not that I have measured anyway.

 

Audible testing confirms this, to quote RacerX

 

"Compared to the Solens, the Russian PIO caps are louder, more lively, and dynamic.  The sound is fuller, has more body."

 

If ESR was high he would have losses especially through the tweeter, it would sound dull and dark, like a blanket covering the speakers. It's the opposite when using these, the sound opens up, cleaner, crisper without fatigue. They just work very well in these speakers.

 

 

 

I did like the original "motor run" caps in my Heresy Type E networks, but the ESR was getting up there and that is when I made the Universal clones. I may have to try some of the Russian PIO caps for the mid & tweeter circuits.

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I use the mid-high section of a pair of original ALK Universal networks. The capacitors used are from Solen and there's one Hovland Musicap.

I always found the treble a bit sharp with my Beyma CP25 tweeters - recently I bypassed the last Solen in line with the tweeter with some Miflex KPCU, 1% value of the caps it bypasses, to good results. Then I decided to bypass the first leg of that 3rd order high-pass with some Russian K75 caps, also 1% of the bigger cap value, and it improved things further. No dramatic change of tonality, no night and day difference, but the high treble has lost all artificial sharpness and edge and sounds now much more natural and "organic". I didn't want to completely replace the original caps and just adding bypasses was an easy thing to do.

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