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Amp with built in driver on an unregulated power supply?

Discussion in 'General CB Services Discussion' started by Dart, Mar 14, 2017.

  1. Dart

    Dart
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    I have a 250 amp unregulated power supply that floats around 17v. I would like to run a 1x6 amp (2290 driving six 2290's) on this power supply. The amp is a custom amp, so I know it can handle voltage, but I'm concerned about the driver section.

    Can an amp with a built in driver be run on the power supply? Or would I have to get the driver section removed or bypassed?



    Thanks for any help.
     

  2. 543_Dallas

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    If it is the usual class C comp style amplifier it will be fine. A regulated supply would be better for any amp but what you're wanting to do will work.
     
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  3. Dart

    Dart
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    Thanks 543. I was concerned that the voltage might be too much for the one pill driver and throw things out of whack, or lead to catastrophe.
     
  4. Robb

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    The candle that burns twice as bright burns half as long . . .
     
    #4 Robb, Mar 14, 2017
    Last edited: Mar 14, 2017
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  5. unit_399

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    EL CAPO

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    HUH ???
     
  6. 543_Dallas

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    If he use a the appropriate drive the candle won't be any brighter or burn any faster than it would on 12.5 volts.

    If this is a class C amp with Toshiba 2879s there will be no issues as long as his swr is low and he doesn't overdrive it.
     
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  7. 543_Dallas

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    No. Just don't overdrive the thing and make sure you antenna system is right. The max carrier out of the amp I would run is 150 watts an keep it under 750 pep with modulation. Maybe less if you get long winded or have the Chinese 2878s.
     
  8. 9C1Driver

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    I see this as, just because you can run 2879's at 17 volts does not mean it's a good thing to do. Their life will be shorter. That said years ago running a power supply like that with a comp amp was no big deal. Toshiba 2879's were 14 bucks. Today if you can find them they are about 55 bucks each. Not worth the risk, get a regulated power supply and run it at 14.5 volts er so. Not my amp or power supply though so he can run it how he wants.
     
  9. Dart

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    You are absolutely correct. Luckily, my power supply will drop under load, so it's going to be around 16V. Yes, I know it's not ideal, but I'm hoping it will go for many, many years.

    I'm old school. I haven't bought into the newer switching power supplies yet. That will take some time for me warm up to them.
     
  10. unit_399

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    I agree. I use an unregulated supply on my linear too. The no load voltage is about 16vdc, and it drops and holds steady at 14.4vdc when the amp is keyed. I like an unreg supply because of its simplicity. Only transformer(s), rectifier, and filter caps. Also, I don't have to worry about it going over-voltage if a pass transistor shorts out. If either the rectifier or the filter caps open or short, the voltage will drop or the fuse will blow, but my amp will live.

    - 399
     
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  11. BBB

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    Just don't overdrive the first stage of the amp that would lead to saturation of the second stage. if you monitor the voltage while you transmit, it will probably drop to 14.5-15 volts under load.

    Great reference...

     
  12. psycho

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    Bypass the driver and run a driver amp on a regulated 20-30 amp supply.
    Running a 6 pill amp on a 250 amp unregulated power supply probably won't drop the voltage much...if any. At $65 a transistor, why take chances and that is why it is so important to properly size an amp to a unregulated power supply.
     
    #12 psycho, Mar 20, 2017
    Last edited: Mar 20, 2017

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