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Should I bake my vintage tube amps???

Discussion in 'Tube Audio' started by Onebean, Nov 9, 2018 at 6:52 PM.

  1. Onebean

    Onebean AK Subscriber Subscriber

    Messages:
    999
    Location:
    Nebraska
    so I’ve recently picked up a couple a Fisher as-100, and a Scott 222b and a Scott 299c. Reading up on bringing these up to full power slowly with my variac per Thatch Ear’s recommendations in the sticky here on tube audio.

    One of his recommended steps is flipping the amp upside down and putting my amps in the oven to bake it. I’m having some reservations about this. My oven only goes down to 170. Is that too hot? Should I do it? If I do it, how long should it stay in???
     

     

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  2. Dswankey

    Dswankey Super Member

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    3,764
    Why did Thatch Ears recommend that? what are the results of putting amps in the oven?
     
  3. Dswankey

    Dswankey Super Member

    Messages:
    3,764
    ^ Disregard, I just read that sticky.
     
  4. Blue Shadow

    Blue Shadow I gotta get me a new title

    Messages:
    21,224
    Location:
    SE PA
    Title made me think 350°F for 30 minutes and it should be well done.
     
  5. cademan

    cademan Addicted Member

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    Was any of your stuff found in a lake?

    It's to bake out any moisture in the transformers but quite frankly, I'd rather wrap tin foil around my fuses! :p
     
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  6. primosounds

    primosounds SE KT120 w/ 6J5G drivers. Subscriber

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    This seems to be a procedure with some rebuilders, but really it seems to be somewhat over doing it. If you are going to rebuild a unit many of the components will be replaced as a matter of course, and then running the rebuilt unit over a couple of hours should get it hot enough to drive any moisture away. It seems like baking it is an unnecessary step, although, i won't argue with the reasoning behind it.
     

     

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  7. GChief

    GChief Not well known, super member or other silliness Subscriber

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    When do this all the time when refurbing MG sets. Pressure wash everything with hot soapy water, rinse then bake at 230f for about 36hrs.
     
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  8. Onebean

    Onebean AK Subscriber Subscriber

    Messages:
    999
    Location:
    Nebraska
    So the verdict is, it's not really needed???

    I'm sure my wife will be happy, I hadn't broke the news to her yet, an I was kind of concerned what it might make the oven smell like.
     
  9. primosounds

    primosounds SE KT120 w/ 6J5G drivers. Subscriber

    Messages:
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    Location:
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    Well, i suppose you could do a poll, which seems to be extremely important nowadays, and see how many do that baking procedure and decide if you want to also try it. I have never done that baking thing.
     
  10. cademan

    cademan Addicted Member

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    9,023
    Me neither although I can certainly understand the reasoning. I have found pieces in mud puddles down dead end roads where I would just let dry overnight or use a blow dryer. I once found a tv that was in a fire and was bogged down with water and ash. I cleaned it out and let it dry for two days before plugging it in. Aside from a warped plastic cabinet, worked great for a few years until I sold it.
     
  11. UncleBingo

    UncleBingo AK Subscriber Subscriber

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    Where did you pick them up? I could see if they'd been sitting in a humid area for years and years,if they were recently waterlogged or if you felt the need to wash them. I've baked transformers at 170 but wouldn't go any hotter. Carbon comp resistors will pick up moisture, so there's that. I would think a week indoors during a Nebraska winter would dry them out plenty.
     
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  12. chip18sw

    chip18sw Active Member

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    I live in NV ... humidity, is not really a big issue around here ... yep 19% right now. :)
     
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  13. Onebean

    Onebean AK Subscriber Subscriber

    Messages:
    999
    Location:
    Nebraska
    To answer some good questions asked. The Fisher came from Colorado (Ebay purchase) most likely it was an estate sale buy and flip. Very little to no chassis rust, so I assume it's been stored properly for most of its life. My Scott 299C came from Kansas City, and again, it looks like it has been cared for. My Scott 222b cam from an AK member living northern CA. This one has been in use recently, so I assume no exposure to heavy moisture.
     
  14. GChief

    GChief Not well known, super member or other silliness Subscriber

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    Location:
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    It will not hurt anything. Not sure about the upside down part.
     
  15. Bob

    Bob AK Subscriber Subscriber

    Messages:
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    I would never put anything into an oven that I would eventually use for food preparation.
    (try scraping some baked on organic material from an oven that needs cleaning and eating it -
    better living through chemistry)
     
  16. maxhifi

    maxhifi AK Subscriber Subscriber

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    If you have transformers potted with tar, if it's upside down, the tar won't leak out. If it's right side up, you will get little puddles.
     
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  17. GChief

    GChief Not well known, super member or other silliness Subscriber

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    Ha, that makes total sense

    :beerchug:
     
  18. kaplang

    kaplang Works for me ! Subscriber

    Bast it with some butter. It will be crisper.
     
  19. crispycircuit

    crispycircuit AK Subscriber Subscriber

    Messages:
    1,431
    Location:
    near Buffalo NY
    Sunshine works the best or if your house has forced air heating, park the unit in front of a vent. Once the unit is working any dampness will go away. Using oven has it's own problems.
     
    savatage1973 likes this.
  20. chip18sw

    chip18sw Active Member

    Messages:
    216
    Location:
    Dayton NV
    All kidding aside, and to be fair ... "Ovens are often used for "things other than cooking. If your into retrofitting "High Discharge Headlights "... into headlights that did not have them or if you have a set of headlights that leak?? You would put them in an "oven" at low heat fort a few minutes, to loosen the adhesive, in order to pry the front of the headlight from the back half of the housing. Then you could replace the adhesive in either case. Of course, it's best done ... when the better half is away from home, if your not a "Bachelor." :)

    I have never heard of doing it with an "AMP??" But it's not that alien a concept?? Most lightly it .. si best to ask lot's of questions before attempting it for the first time, preferably from someone that has done or does it.
     

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