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The next generation of linear amplifiers has arrived.

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

  1. Shockwave

    Shockwave Sr. Member

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    Three more PA stages have been built, aligned and tested using my new design. Several splitters and combiners are being evaluated for their performance characteristics in the circuit now. The experiment is expanding quickly. The goal here is to see if at least 1500 watts PEP can be produced from a 15 amp 120 volt AC circuit. Early tests indicate this will be possible at about 11 amps average for the first time using this high efficiency design.


     
    #76 Shockwave, Sep 11, 2019
    Last edited: Sep 11, 2019
    CB590 and Shadetree Mechanic like this.

  2. Shockwave

    Shockwave Sr. Member

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    Sometimes it's just a matter of loading an existing transistor die into another existing package that has much lower thermal resistance. In that case, there are no upfront costs. Someone just has to load different dies on the packaging assembly line. Kind of like Maco did with GE when they placed the right minimum order to have the guts of the 8908 tube loaded into a 12 pin Compactron base known as the M-2057.
     
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  3. nomadradio

    nomadradio Analog Retentive

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    And change the heater to 12 (or so) Volts.

    RF beyond the kilowatt threshold from a 120-Volt circuit was always a "holy grail" for CB base operators. Some of the legal-limit solid-state ham amplifiers offer only reduced power when powered from a 120-Volt circuit.

    A proper bank of low-pass filters and the hams will be beating a path to your door for this one. Installing a 240-Volt circuit is a significant barrier for a lot of operators.

    73
     
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  4. Shockwave

    Shockwave Sr. Member

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    That is the direction this is headed. Many output filter boards are already available that would be compatible with this design. Some have directional couplers that would simplify interfacing my protection circuit for high VSWR, while providing accurate power readings to drive the meters. These models can easily have their power supply configured in a way that is field selectable for either 120 volt at 11 amps or 240 volt operation at 5.5 amps average. Now that the protection is working well, there is no concern about the operator selecting the wrong band filter at full output.
     
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  5. Shockwave

    Shockwave Sr. Member

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    Are you aware of any linear amplifier that can produce 1500 watts PEP through 10 meters, from a 120 VAC 15 amp circuit? I thought they were all reduced down by at least 1200 watts PEP under those circumstances.
     
  6. nomadradio

    nomadradio Analog Retentive

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    I said "some" as a hedge.

    Besides I'm not familiar with all of them anyway.

    73
     
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  7. Shockwave

    Shockwave Sr. Member

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    I was just curious if there was one I overlooked. No offense meant.
     
  8. Shockwave

    Shockwave Sr. Member

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    Just finished the third video demonstrating the full electronic protection in the new amplifier design. While common LDMOS amplifiers (BLF188XR) brag about their durability, the truth is, only the output is durable. The input gate is still very fragile. Apply too much bias or drive and those transistors are easy destroyed. Doing both simultaneously without full protection, will guarantee the failure of any solid state output device. This technology renders those problems a thing of the past, while consuming less space and input power than anything previously designed.

    At 48 seconds in, bias and drive are being increased in order to force the protection circuits to fire. When this happens for the first time, the view of the amplifier is blocked, but if you look to the left you can see the output Bird meter in the background. It is out of focus but if you know where the numbers are, the word "drive" approaches 900 watts PEP and the word "bias" hits 900, exceeding the preset limits of protection. The output on the Bird (and panel meter on amp) also drop to drive levels on the word bias, as protection has been triggered.

    The Diamond meter was suppose to show a 3:1 VSWR condition, also triggering the protection from the output side. However, it wasn't recalibrated after the increase in reflected power. The cross needles on the antenna tuner did capture the 3:1 condition. None of these test conditions have placed any of the parts used in this design, past about 50% of their ratings.


    The new video can be viewed at this link:
     
    #83 Shockwave, Sep 18, 2019
    Last edited: Sep 18, 2019
  9. AudioShockwav

    AudioShockwav Extraterrestrial Admin
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    Wow.
    That is a very impressive video!
    73
    Jeff
     
  10. Shockwave

    Shockwave Sr. Member

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    Thank you.
     
  11. nomadradio

    nomadradio Analog Retentive

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    Once these are sold in any quantity, the most-popular mods posted on the internet will be to bypass the protection circuits.

    To get Mo Watts.

    For a brief moment.

    73
     
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  12. AudioShockwav

    AudioShockwav Extraterrestrial Admin
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    Lol@ Nomad!

    What you mean I can't hit it with my 4 pill driver?
    Must be a diode in there I can clip......
    Doctor Mo Watts
    Really,
    This is the best thing I have seen in solid state amps in a long time.

    73
    Jeff
     
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  13. Shockwave

    Shockwave Sr. Member

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    If that's the goal, a typical BLF188 amplifier is the best bet. It probably won't have any of these expensive protection circuits to block someone's desire to burn up output transistors. Plus if you start disconnecting these sensing circuits, that alone will inhibit operation since the board would not be able to confirm if the device was within the Safe Operating Area and lockout the amplifier. One would have to figure out how to trick it into thinking the proper conditions have been met. Just forcing the output relay to key, will not send the correct signal to the bias circuit in order to pull the transistor out of cutoff.
     
    #88 Shockwave, Sep 18, 2019
    Last edited: Sep 18, 2019
  14. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    Any idea what price range this will be in when it becomes available? You can sign me up to be a beta tester.(y)
     
  15. Mudfoot

    Mudfoot Sr. Member

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    Martin Jue beat you to the punch.
     

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