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Dentron Clipperton L 572b Tubes?

Discussion in 'Amateur Radio Amplifiers' started by KE0KDQ, Oct 25, 2018.

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  1. KE0KDQ

    KE0KDQ Ham Member QRZ Page

    Bought a new-to-me amplifier which showed up poorly packaged and with one of four 572b tubes shattered.

    Questions:

    1. Can this amplifier be used with just three tubes?
    2. Can I simply replace one, or two of the tubes? Which ones?
    3. Anybody have a set of up to four laying around they'd be willing to part with?

    Thanks,
    KE0KDQ
     
  2. KD2ACO

    KD2ACO Platinum Subscriber Life Member Platinum Subscriber QRZ Page

    I think you can replace one. If you want a set, here's a post from a few days back that's not much more than the cost of one.

    https://forums.qrz.com/index.php?threads/572b-matched-quad.632047/

    edit:

    Oops, I just checked that listing and they've sold already, sorry... back to our regular program.

    Send me a PM, I've got a couple lying around with no amp to go in.
     
    Last edited: Oct 25, 2018
  3. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    If one was shattered (no big surprise if they were all installed when shipped), be careful about the other three.
     
  4. KD2ACO

    KD2ACO Platinum Subscriber Life Member Platinum Subscriber QRZ Page

    Good point^^^
    Here's the tube off of my shelf that I was thinking about parting with. It's a mid '73 Cetron that looks good except the grid deflector post was bent a bit during the spot welding step.
    I could guess that this tube passed all the tests at Cetron before it was boxed but I haven't tested it in an amp.

    What do you think, Steve? Have you run into this before? Does it stand a chance of not killing an amp or should I toss it? Bigger pics with a click.

    Cetron T160L.jpg P1010175.JPG P1010177.JPG P1010179.JPG

    Turn the amp on with a broomstick? :p
     
  5. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I have no idea and don't own anything with 572Bs or even 811As in it.

    Smallest tube I have in any amp is a 3-500Z.
     
  6. N7WR

    N7WR Subscriber QRZ Page

    I have a Dentron Clipperton L and fortunately the 4 tubes in mine are solid. WOW I just checked at the cost of 572B's from RF parts as I was considering buying 4 as back up...heck a single 500 Z is less expensive.
     
    WA4BCS likes this.
  7. AC0OB

    AC0OB Subscriber QRZ Page

    Are the other tubes damaged? Take them out and see if there are any particles rolling around. Check the filaments to see if they taught and in position.

    I have a Svetlana, NIB, 572B I could part with.




    Pheel
     
  8. KE0ZU

    KE0ZU Ham Member QRZ Page

    You should be able to run the amp with 3 tubes, I've run amps with tubes missing with no harm for a year or better.
     
  9. KA9JLM

    KA9JLM Ham Member QRZ Page

    The filament voltage may be a bit high.
     
  10. DL3LK

    DL3LK Ham Member QRZ Page

    Thats wrong! Only with 4 Tubes you have a input r of about 50 Ohms.
    One groundet grid 572 has a input r of 215 Ohms.
    You will have a missmatch in your input circuit.

    73 de Volker DL3LK
    TS590 and Dentron 160-10L (4x 572b)
    (Sorry about my english)
     

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