How does a tube amp work?

Discussion in 'Tube Audio' started by BmWr75, May 15, 2012.

  1. BmWr75

    BmWr75 Addicted Member

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    I don't know why all the links to pictures are broken in this sticky. Maybe it happened when the forum was migrated to this new format. Anyways, I can no longer edit old posts to reconnect the picture links. Sorry.


    ------
    (Kegger)

    Yah server migration messed up a lot of links/pic's, don't know if they'll get fixed, to much work to do them all manually..
     
    Last edited by a moderator: Jan 31, 2016
  2. kcvet

    kcvet Active Member

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    After power off a bleeder resistor will drain B+ very quickly..

    If there of small enough value, otherwise they will drain slowly..
     
  3. ToasterBin

    ToasterBin Toasterbin Subscriber

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    Ok, that first line caused me to wet myself. I'm a tube newbie, and now I read this line and ask myself WTF? I picked up a Musical Paradise 301 MK3 and the Loth X BS-1s speakers from Bostown that has yet to arrive, and does not concern me (overly) much, but I also picked up a HK Festival 2 in need of repair. Now, I know enough to know I don't know enough. But, its clear I didn't know how much I still don't know. Should I buy a bomb defusing device to carry the HK into a concrete bunker? I've not plugged it in so wonder if there is there any advice that can be offered before I do so for the very first time? It is also without the full case (meaning no top).

    Help me obi wan kanobis; you're my only hope.
     
  4. Dandy

    Dandy Super Member

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    Here's the HK manual with schematic. http://manuals.harman.com/HK/Owner's Manual/Festival2 TA260 om.pdf

    It'll have about 360V on the plates of our power tubes, so not quite 500V. There are many threads on AK advising on what do before preparing to power up a vintage amp for the first time. Do a search. If you've done a visual check and nothing seems amiss, you can take your chances (with a lamp limiter in circuit), or do a proper recap first.
     
  5. ToasterBin

    ToasterBin Toasterbin Subscriber

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    Hi Dandy,

    Thanks...should have done a search first. That first line just...er, "shocked" me a bit, though I do know with any electrical equipment to be careful of the innards. I'm in no hurry, so will do a proper recap when I get around to it.
     
    Dandy likes this.
  6. Dandy

    Dandy Super Member

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    The DC stored in the capacitors can be 'shocking' even when these are switched off. I accidentally discharged a 50uF 450V cap by touching it when trying to build my first tube amp. My reflex flung the amp right across the room and gave me a wavy grin for the rest of the day. So, the other rule is discharge the high voltage caps before working on tube gear.
     
  7. ToasterBin

    ToasterBin Toasterbin Subscriber

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    I'm still considering the robotic bomb diffuser and the concrete bunker...
     
  8. Dandy

    Dandy Super Member

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    Heh heh. The good old days. I remember powering up my first Dynaco from the other side of the room, via a lamp limiter on a long lead, and hiding behind an armchair just in case. The adrenaline rush, followed by the thrill of sound, is addictive.

    It would be worth starting a fresh thread to talk about getting your HK Festival II working.
     
  9. ToasterBin

    ToasterBin Toasterbin Subscriber

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    I wondered how you got the nickname "One Handy Dandy"
     
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  10. WopOnTour

    WopOnTour Hoarder Extraordinaire

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    A couple of pretty good videos outlining a simplified theory of operation primer (using guitar amplifiers)
    Enjoy
    WOT

    Part1


    Part2
     
  11. Salguod

    Salguod Member

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    I've been reading a little bit. I used to work at cl2-3 in Freeport Texas. Also made Magniseum at the same sight (which was like the same process). We brought in 15kv and rectified it to DC then sent it through (what we called a regulating transformer). The cl2 cells that had a cathode and a anode and a asbestos diaphragm.
     
  12. Salguod

    Salguod Member

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    If my memory serves me right we ran the chlorine calls at 72000 ka
     
  13. Salguod

    Salguod Member

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    Chlorine cells! Mag cells we ran about 55 KA
     
  14. Salguod

    Salguod Member

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    I'm sorry cl2 cells 72ka
     
  15. Salguod

    Salguod Member

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    Would the asbestos diaphragm be the grid? Because when it got we voltage would go up and that was bad! Maybe I'm crazy.
     
  16. Salguod

    Salguod Member

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    Sorry, When The diaphragm got high voltage (resistance) it was ready for a new cl2 cell.
     
  17. Salguod

    Salguod Member

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    35 years later I still work at that sight. But we take c3h8 and convert it to c3h6.
     
  18. Salguod

    Salguod Member

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    A old friend that I used to worked when had a flash a couple of weeks ago. He didn't discharge the batteey
     
  19. Salguod

    Salguod Member

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    He is had some burn threopy
     
  20. Salguod

    Salguod Member

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    Are was on a charged battiery
     

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