Russian Teflon caps

Discussion in 'Tube Audio' started by nj pheonix, May 14, 2018.

  1. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    I know there's a bit of dissension here about cap break in , in general.
    Its been my experience using the Russian PIO caps that there is a break in period. If you disagree i respect your opinion but for the sake of this discussion let's not go off track please.
    So , if you're with me so far and agree that if takes some time before they are done doing whatever that might be. My question now goes to, is there a similar break in period for the Teflon Russian caps ? I've never used them before but I'm planning to use them in something in the future. Thanks in advance.
     

     

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  2. Brice

    Brice AK Subscriber Subscriber

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    Hi Andy,
    I use them a lot. And they are my favorite caps, when they fit...

    Break in period is very long. For 10 hours, it is good. Then from 10 to 50 it is horrible, all fuzzy and messed up.

    You think you've made a big mistake: just stay cool and carry on.

    After 50 hours it is better but it really opens up after 100 hours.

    Then these caps are absolutely fantastic. Clarity, details and no alteration. Superb cap.

    I do shrink wrap them.

    20171006_151114.jpg
     
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  3. tube-a-lou

    tube-a-lou Super Member

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    I don't know about Russian Caps but I find that the Sprague PIO's I have in my Fisher KX200
    sounds better when it's on awhile, it just opens up more.
     
  4. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    Brice ,
    Did you lace up that harness?
    That's pretty!
    Oh , thanks for the comments.:thumbsup:
     
  5. Brice

    Brice AK Subscriber Subscriber

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    No, was from the factory. Yes well build. Allen Organ.
     
  6. gadget73

    gadget73 junk junkie Subscriber

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    I'd be tempted to try and shortcut that whole breakin process by just running them at full rated voltage for a while. Hook them all up to the cap tester and let it cook for an evening.
     
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  7. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    I think i read somewhere , where someone used some kind of sweep generator and an amp to do just that. I like the idea but i have neither:dunno:
     
  8. Brice

    Brice AK Subscriber Subscriber

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    Yeah, I thought about doing that.

    Having my B+ PS generating 400VDC, and adding a AC voltage into it through the caps into a grounded resistor.
    But then I'll cook my PS tubes, ha ha.

    I don't think you need to push them at full voltage, just having a nice AC amplitude through the cap is more important IMO.
     
  9. gadget73

    gadget73 junk junkie Subscriber

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    I'd want them at full DC voltage to form them completely, and to make sure they weren't going to leak. No AC needed.
     
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  10. Brice

    Brice AK Subscriber Subscriber

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    Interesting. I though we want to have a minimal AC current going through and not just a DC check.
    I'll need to build myself a SS high voltage supply. I don't want to burn my PS tubes...
     
  11. Morzh

    Morzh Active Member

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    Almost went to work for them in 1990. In Long Island. As a repair tech.
    And then once more in 2000-something, when they went into telecom by acquiring Eastern Research, as an EE.
    But ended up elsewhere. Otherwise I'd learn to make that harness :)
     

     

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  12. primosounds

    primosounds SE KT120 w/ 6J5G drivers. LCLC ps + 2 x 5ar4 Subscriber

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    I am using the FT3 teflon caps in a SE KT120 amp. I am guessing over 200 hours of playing time on them and in my use i did not find any radical change in the sound quality. Right now everything about the amp seems to be good and the coupling cap is not something i am worried about. So as far as i am concerned it is about perfect , which is totally out of the way or neutral. About the only thing one needs to worry about is to make sure you space your tubes to allow for their very large dimensions.
     
  13. hjames

    hjames dancing madly backwards ... Staff Member Moderator Subscriber

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    I used huge Russian Teflon caps in my Heath "Valencia" crossover rebuilds,
    the big green cans!

    Crossover_6600.jpg
    Crossover-New_6612.jpg
     
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  14. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    On forming them at voltage , if the cap were say 1000v, but the circuit no more than say, 300v, would you form at or near 300 or 1000?
     
  15. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    That's a pretty big cap .
    I wouldn't want to have to stuff that in an amp.
     
  16. hjames

    hjames dancing madly backwards ... Staff Member Moderator Subscriber

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    Agreed!

    CapKit_6410.jpg
     

     

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  17. primosounds

    primosounds SE KT120 w/ 6J5G drivers. LCLC ps + 2 x 5ar4 Subscriber

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    By forming, do you mean, like in electrolytics? There is no reforming of film of signal type caps. In electrolytics, the chemical composition requires the development of the insulating film by voltage.
     
    Last edited: May 16, 2018
  18. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    I was going on the premise that Gadget had this right. He generally does.
    I didn't think films formed. Perhaps it was the wrong choice of words.
    Because nobody ever gave me a plausible idea what happens when these change , I've always been at a loss what was happening.
    Just my opinion (well I know I'm not alone) something sonically happens to the PIOs. I did assume it was the variation in frequency and amplitude that somehow brought it about. I haven't noticed it in polypro, polyester, and other films. Also the teflons don't have PIO in their description so (again I'm assuming that the construction was entirely different than the ky40s.
    I do know several years ago I used pio mundorfs, and when I contacted them , they said 100 hrs
    I realize this is somewhat apples to oranges.
    I will be trying this out (expect delivery in about a week. Unless I have time , I may just run on a CD repeating into a resistive load and walk away for a few days.
    This won't be too telling also because I'm piggy backing them on a larger cap to achieve a higher value so they won't be the only cap in circuit and they're only slightly more than a tenth the value of the cap they're adding too.
    At the proper value I think they'd be as big as coke cans (maybe an exaggrration) so that was never an option.
     
    Last edited: May 16, 2018
  19. gadget73

    gadget73 junk junkie Subscriber

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    I'm not so much concerned about forming them as leakage testing. If it will run at full rated voltage without leakage, the internal insulation is fine.
     
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  20. primosounds

    primosounds SE KT120 w/ 6J5G drivers. LCLC ps + 2 x 5ar4 Subscriber

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    Oh, i misunderstood. You are talking about 'break in' period. Yeah, this seems to be a well recognized but still mysterious phenomenon. I suppose it could be some kind of "reforming" of sorts. I had a very eye opening experience of this when i rebuilt a Marantz 7 preamp. The owner wanted to put in Russian K40-y9 caps. So, i got them installed, and after verifying that all was ok at the shop, i brought the Marantz 7 home and installed it in my reference system. I queued up the Oppo player with my usual test cds like, Dire Straights Brothers in arms, and after a few notes of music i knew right off the first guitar riff. Woah, this sounds lackluster, i might have to tell my buddy that these K40s are a mistake and we should probably try something better. So, after few hours of various other test cds that i always play for sonic impressions, i shut it off and was rather disappointed. Next day i used the preamp more and just decided to keep on playing it.. After doing some research i learned that other guys had noticed that there is a break in period for these caps. And sho nuff, after 20 to 30 hours, the sound from the preamp started to grab my attention. And playing the same test cds that i used in the first test they all sounded like they should. I returned the unit to my audio buddy and he was very happy with it. I had not run across such an obvious break in issue like that before. To be sure, i also rebuilt the power supply for the preamp so maybe that was part of it.
     
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