Russian Teflon caps

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

  1. gadget73

    gadget73 junk junkie Subscriber

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    well, I also suspect that running them at voltage would accelerate any break-in that may occur. Whether that happens at all or not is too endless an argument for me to be interested in. I think I've heard it on things before, but I've got other gear that sounded exactly the same the first time I turned it on with all new parts as it does now.
     

     

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  2. Brice

    Brice AK Subscriber Subscriber

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    Yes I agree. PIO and Teflon and film foils caps need a break-in period. Teflon been the longest of all.
    I suspect it has to do with alignment in the structure of the metal foil. And if you break them in "artificially" you should note the high voltage side of the cap, to mount it back in the amp the same way.
    Found some SS high voltage supply for very cheap, I'll try this, but will also add a small 1K signal on top the the DC just to "make the cap pass signal", into a resistor to ground.
    My Sencore cap tester does it up to 600V, but I have to press a button for it to work.
     
  3. primosounds

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

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    Brice, you could bypass the switch with a test lead with alligator clips. If your cap tester doesnt mind doing that for awhile.
     
  4. triode17

    triode17 Well-Known Member

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    I run all caps though my 'test of three': 1. Value 2. Leakage 3. ESR Then once the circuit is working with them properly, I will burn them in using a Pink Noise generator for a few hours. I then run the piece in two hour shifts. I believe that tensioning the parts and un-tensioning them kind of tempers them into sounding better. Overall, I find it generally takes 8-12 hours to break- in passive parts. Then, once I hear an improvement in sound that I didn't expect, I know they are broken-in. A friend of mine noticed the same improvement effect after some running time.
     
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  5. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    Experiment will have to be tried at a later date. I opened box this afternoon and held one up in the place i intended. Its not going to happen. It could conceivably be kludged but that's not my thing. I had this fear (concern maybe?) in the back of my mind so i ordered Polypro films about the same time and that will be the final answer. Someday maybe:dunno:
    On a more positive note , i think they're pretty cool looking (if you're into that kind of thing) Someday i'll find something to do with them. Thanks for all comments, opinions, and guidance:thumbsup:
     
  6. Brice

    Brice AK Subscriber Subscriber

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    Np. I bought a HV supply, a white noise generator and a digital Amp/V meter in one.
    Once I get that together, I'll use this to break in expecially Teflon caps.
    I'll report then.
    Cheers
    Brice.
     

     

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  7. nj pheonix

    nj pheonix AK Subscriber Subscriber

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  8. cyto

    cyto Well-Known Member

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    I am a big fan of Russian teflons, they do seem to sound different after a while. When I get any I hook them up to a 12vac walwart with a 10k resistor for a week or two.

    I was a licensed CET back in the 70s (got out of electronic and got into the medical field) so I have always been skeptical of capacitor break in. But some caps do sound different after a while so who knows.

    caps.jpg
     
  9. Brice

    Brice AK Subscriber Subscriber

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    I put something together.
    It's a white noise generator and a HV switched supply. It generates up to 1KV, and I am adding a white noise signal on top, few volts.
    I put it in a box quickly and get it going for days. I already put 153 hours on those 0.22uF Teflon caps at around 450VDC.
    I honestly thought the Chinese HV supply will give up, but no, still going.
    I'll stop around 200 hours.

    20180602_105832.jpg 20180602_131853.jpg
     
  10. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    Brice ,
    Did you try and take any kind of measurements prior to hooking up to your set up?
    I was reading an article by Conrad Hoffman last night about caps with different dialectics and their possible effects on audio.
    A few more tests than C and ESR, nothing conclusive but some (perhaps?) interesting observations
     
  11. x3workshop

    x3workshop AK Subscriber Subscriber

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    Got a link to that article?
     

     

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  12. Brice

    Brice AK Subscriber Subscriber

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    Just the C and DC leak as my Sencore does not give me the ESR.
    And C was sharp 0.22 with 0 uA leak at 600V.
    I'll measure them again at 200 hours.
    And I marked the negative side od the cap as I believe this matters when re-installing them an actual amp.
     
  13. nj pheonix

    nj pheonix AK Subscriber Subscriber

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  14. Brice

    Brice AK Subscriber Subscriber

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    That's interesting: Teflon and Polystyrene seems the best, as well as in his testing and in the audiophile community.
     
  15. GregBilodeau

    GregBilodeau AK Subscriber Subscriber

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    I have a used a few of the Russian TFE caps and they do seem to sound good but at this point I have had two of them fail and both were dead shorts. Lucky I was sitting there when it happened and watching the plate on one of my GEC KT88 tubes glow bright red was not a great experience. The second was in a customers amp and same thing, dead short. He did not notice right away and it cost him a tube as well and lucky for him not a transformer.
    I have since removed them from my amps.

    Gregb
     
  16. Brice

    Brice AK Subscriber Subscriber

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    Wow Greg, I am very surprised.

    Was it the FT-3 or the K72-P model?

    Thanks
    Brice
     

     

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  17. GregBilodeau

    GregBilodeau AK Subscriber Subscriber

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    Hi Brice:
    I don't have them handy to check what series they are but the one that I had fail was the same as what is offered as the cap upgrade in the Tubes for HiFi ST120 amp kit. They are a rather large silver bodied cap with the glass sealed ends.
    The customer repair was one of the green bodied ones, again I don't recall the series.
    Both of these failures were in the last 5 years.

    Gregb
     
  18. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    I'm pretty sure those are paper in Oil K40y9s not teflon
     
  19. Brice

    Brice AK Subscriber Subscriber

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    Thanks Greg, I also suspect it is PIO caps not Teflon.
    The Teflon caps are huge.

    Here is a pics I just took of both models, so you can appreciate the size difference.

    Thank you.


    20180610_152118.jpg
     
  20. GregBilodeau

    GregBilodeau AK Subscriber Subscriber

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    OK, the one I had fail was the bottom one pictured so not Teflon then. The customer one was a green one that was smaller yet and it was a dead short as well. I will have to watch for some of the Teflon ones then.
    Sorry for the confusion, I thought I was told they were Teflon but guess not.

    Gregb
     

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