Transmitter tubes of recent production are prone to easily break, aren't they?

Discussion in 'Amateur Radio Amplifiers' started by JL1DCA, Apr 28, 2017.

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  1. JL1DCA

    JL1DCA Premium Subscriber QRZ Page

    You are already back in NYC, are you?
    Yes, I'm anxcious for visiting Jazz spots and listening to native NYC musians play.

    Fans driven with 12VDC are available in Akihabara.
    I'll try it.

    Taihei Suzuki
     
    KD2ACO likes this.
  2. VK3BL

    VK3BL Premium Subscriber QRZ Page

    15 seconds is nothing for a pair of 572Bs - they likely wouldn't even develop plate colour unless severely mistuned.

    I ran my AL-572 with 4x572B tubes into a dummy load at 1200 watts output single tone for over a minute until the power outlet board ended up popping its safety switch due to overheating.

    Its more likely your tubes were old or you got a bad set. A good set of 572B tubes can take a real beating unlike 811As, which much more readily suffer cathode poisoning when overheated.
     
    NQ1B and AF6LJ like this.
  3. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    I've heard from a couple of folks recently that state that the FL-2100 isn't good at shedding heat, and according to the manual, it seems like this is true. 5 seconds on and 10+ off when tuning is recommended.

    It seems that even with a decent helper fan, it's probably best to go easy on the thing...
     
    AF6LJ likes this.
  4. JL1DCA

    JL1DCA Premium Subscriber QRZ Page

    Hello, Chris and VK3BL

    I have now a 12cm-square-sized assistant fan placed on top of the FL-2100Z straight above the tubes. The fan is driven by 5VDC for nominal 12VDC .
    I hope it helps anything.

    Taihei Suzuki
     

    Attached Files:

    Last edited: May 20, 2017
  5. JL1DCA

    JL1DCA Premium Subscriber QRZ Page

    I wonder if FL-2100Z is designed to sustain new 572B's consumption.

    Is it a 572B abuser ampilifier??
     
  6. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    I really don't think so! :p

    It's a nice looking amplifier with a good power supply. It seems that it is really designed to get some peak power output with low duty cycle signals like SSB and for that, it's a lovely amp according to one of my pals at the radio club.

    What modes are you using the FL-2100 for?

    cheers,
     
  7. WA6MHZ

    WA6MHZ Premium Subscriber QRZ Page

    Just don't drop them. That is when they are most likely to break. I put my 3-500Zs in a box wrapped in bubble wrap the moment I got my SB-221 home!!! They are safe there for now
     
  8. JL1DCA

    JL1DCA Premium Subscriber QRZ Page

    Dear Chris,

    Almost entirly in SSB. Aside from when attempting a overseas QSO, I run a barefoot power or even way less in CW.

    Taihei Suzuki
     
    Last edited: May 20, 2017
  9. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    Well, great! I guess with TL160's installed and that outside fan running at low speed so it is quiet, you'll be fine.
     

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