Vac Tube Lamp

Discussion in 'Homebrew and Kit Projects' started by KD8EUR, Sep 17, 2008.

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  1. KD8EUR

    KD8EUR Ham Member QRZ Page

    One of our local hams went SK and in cleaning out his stuff I found a lamp he was making out of old vac tubes. He got as far as making a nice wood box to hide the sockets and a top to hold the tubes in place. I'm thinking it might be neat to finish the project for him. My question is what kinda of power do I need to light the tubes up? The tubes have WL-468 on the bases and they're big guys. About 12 inches tall from base to tip.

    Anyone have any ideas on what I should do to light these guys up?

  2. KD8EUR

    KD8EUR Ham Member QRZ Page

  3. KL7AJ

    KL7AJ Ham Member QRZ Page

    Well, you're going to need a pretty beefy filament transformer. It won't be a "green" operation, to be sure. :)
  4. W4HAY

    W4HAY XML Subscriber QRZ Page

    Try using a search engine for the tube # and "specifications".

    Typically, Thoriated filament voltages run around 10 Volts and bunches of Amps. An 810 has about the same size plate and requires 10 Volts at 4.5 Amps, so you'll need a hunky transformer. If you're going to use several tubes, consider clustering them around a small amber bulb, maybe from a Christmas tree string.
    Last edited: Sep 17, 2008
  5. KD8EUR

    KD8EUR Ham Member QRZ Page

    Hmm maybe I'm figuring out why the project never got done.

    So this is the kinda thing I can hook up to my 12vdc power supply that runs my rig.

    I've done some google'in on these tubes and really can't find too much in the way of specs. Even if I never light them up I think I'll clean then up and put them out on a shelf. They're pretty neat to look at.

    Thanks for the help,
  6. W4HAY

    W4HAY XML Subscriber QRZ Page

    WHAT? You haven't started your electronic nic-nac collection yet? My wife has her Precious Moments figurines and teapots, I have my firebottles and glowbugs.

    Keep your eyes open at hamfests, especially for the ratty old boxes under the tables. There can be some really unique -- and beautiful* -- items down there.

    You can simulate a socket for many tubes by drilling holes in a piece of hardwood to match the pins, and placing a thin slice of PVC pipe between the tube base and the wood. It's hard to tell from a ceramic socket.

    *Beauty being in the eye of the beholder
  7. KD8EUR

    KD8EUR Ham Member QRZ Page

    Well I'm glad I'm not the only one who thinks this stuff has a beauty to it. I think I could become a hardcore tube collector if I let myself. But I need more stuff like I need another hole in my head. haha

    Thanks again,
  8. KD0DQZ

    KD0DQZ Ham Member QRZ Page

    Saw one made out of a dud 833 once...guy had let the air in and snaked a wire thru the tube to an ordinary socket mounted on either the plate or grid cap. He held it under water in a bucket and snipped off the glass nipple between the filament pins with a diagonal cutters. The water rushing in prevented the glass from imploding. Stood the tube up, drilled a small hole in one of the top caps and let the water drain out. He used a diamond bit in a Dremel to enlarge the opening in the glass to allow ordinary lamp cord to pass through. Evidently the toughest part was snaking the cord through the tube...but, mounted on a wood base with a socket and shade on top made it look pretty cool. Used a LOT less juice as well.
  9. K9STH

    K9STH Ham Member QRZ Page

    Depending on the tube the filament/heater can have a completely different voltage requirement. Some tubes take as little as 1.0 volts and some require over 24 volts. Most tubes require one of the following voltages:

    2.5 volts
    5.0 volts
    6.3 volts
    10 volts
    12.6 volts
    35 volts
    50 volts
    110 volts

    Of course there are all sorts of "odd ball" voltages used in the old AC/DC television sets which were developed so that the filaments/heaters could be run in series from the 117 VAC line without need for any series resistors.

    You have to supply the proper voltage (within a very few percent) to get the tube to light. Too little voltage and the filament/heater will not give off any visible light and too much voltage and the filament/heater will burn out in a hurry.

    Do a "google" on the tube type and you can generally find the specifications which will tell you the filament/heater voltage and the current drawn.

    Glen, K9STH
  10. KD8EUR

    KD8EUR Ham Member QRZ Page

    Hi Glen. Are those voltages AC or DC? I found very little on these tubes in the way of specs. Do tubes generally run AC or DC or are there just a mix of some of one and some of the other?

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