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The next generation of linear amplifiers has arrived.

Discussion in 'Amplifiers' started by Shockwave, Sep 5, 2019.

  1. nomadradio

    nomadradio Analog Retentive

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    Cool!



    Just thinking out loud. An old friend had a spurious-trip problem with his 80-meter dipole. The breaker panel was in the adjacent room in his basement. Odd part was that the breaker that was tripping was not the one that served his radio room. Might not have been the ground-fault side of the breaker. Could have been the arc-fault sensing that was causing the nuisance tripping. He changed out the breaker and the problem went away.

    73
     

  2. Shockwave

    Shockwave Sr. Member

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    Older ones were much more susceptible to nuisance tripping. The longer the wire is after the GFIC, also contributes to false triggering. Mounting at the equipment end solves that issue. Incidentally, one of the first ones I tried was a GFIC cut off the line cord of an old Goldstar air conditioner.

    When it wouldn't trip with a 1 amp load across the line and ground wire (not neutral), I had to crack open the Chinese junk and see why. What a piece of deception that was inside. The entire sensing circuit was absent and replaced with a single transistor connected to the reset button in order to fake the test!
     
    Shadetree Mechanic likes this.
  3. nomadradio

    nomadradio Analog Retentive

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    Keeping it inside the amplifier cabinet at least allows you to control filtering and bypassing to/from the thing.

    And yeah, it's not "listening" to the safety-ground conductor, only to the hot and neutral for any imbalance.

    Haven't seen a fake one yet. Just a matter of time, looks like.

    Some days it's hard to resist being the devil's advocate.

    73
     
  4. Shockwave

    Shockwave Sr. Member

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    I had to go back and look at that Goldstar AC unit with the fake GFIC to see if it carried a UL approval sticker. It does! Hopefully the GFIC was "modified" after their inspection...
     
    Shadetree Mechanic and CB590 like this.
  5. Unit 148

    Unit 148 Unit 148 Mobile CYPRUS

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    I read earlier in this thread about holy grail power supplies and efficiency numbers. We use two of these extremely compact and highly efficient in our commercial 1kW FM broadcast transmitter (FCC ID'd but produced in the UK). Have enclosed the pdf. They are hot-swap as well so you're not off-air if one shuts down. Here's the transmitter video: Shockwave, I've designed a 'mobile' chassis for you when you're ready to produce that all-band version of your amplifier + remote head :) Unit 148 mobile - G4ZOW
     

    Attached Files:

    Shadetree Mechanic likes this.

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