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tuner before amp

Discussion in 'Amplifiers' started by 552fl, Oct 1, 2018.

  1. 552fl

    552fl Active Member

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    2-pill driver into heathkit sb-220...someone suggested putting a antenna tuner inbetween driver and sb-220??


     

  2. n8fgb

    n8fgb Well-Known Member

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    LOL
     
  3. 9C1Driver

    9C1Driver Sr. Member

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    I wouldn't. What radio are you running? A 2 pill driver for that amp seems a bit much. I'm guessing 80-100 watts would be all that amp needs to do 1000-1200 watts. Might even coast along at 700 watts with only 50 watts of drive.
     
  4. 552fl

    552fl Active Member

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    They said that it would tune the input of the 2 pill going into the Heathkit tricking it to 50 ohms was just wondering if anybody has tried it.. I have the variable turn down on the two pill so is that it is doing about 90 Watts Peak. When you're talking about 100 Watts what are you talkin average or Peak Watts going into it curious.. what should be the a good dead key with the 2 pill key down on the Heathkit SB 220
     
  5. 552fl

    552fl Active Member

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    Oh I forgot running a Galaxy 2517 turn down to two and a half what swing into 15
     
  6. 543_Dallas

    543_Dallas Sr. Member

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    Why do you think you need a tuner between the driver and the sb220? If the input swr is high something is wrong with one of the amps or the tubes in the sb220 are soft.

    I wouldn't run the sb220 at more than 100 to 150 watts carrier. The cooling system and hv power supply aren't good enough to handle much more. Run it in cw mode on AM.
     
  7. 552fl

    552fl Active Member

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    Is that 50w bird or or is at 50 Watts Peak into the sb220
     
  8. 552fl

    552fl Active Member

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    tubes are next....machlett 3-500zg
     
  9. 552fl

    552fl Active Member

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    In the book it says it 100 Watts but that was back in the day average power..
     
  10. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    No offense but God I hate seeing things like this. There are no such things as Bird watts. That is something CB'ers came up with. A Bird meter can read average watts or if it is a pep Bird meter it can read peak watts so saying Bird watts or peak watts is completely wrong and meaningless. The SB220 was designed to be run with a typical 100 watt transmitter. If you drive it on SSB with 100 watts pep then that is fine. if you want to hit it with a 100 watts UNMODULATED carrier as in CW mode that is fine. just don't hit it with a 100 watt AM carrier and then expect to modulate that carrier.
     
  11. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    Again that is not quite right. That 100 watt input rating is as I described above. Peak versus average has nothing to do with "back in the day". The only thing about back in the day is input power versus output power. Old amps were rated in input power whereas today they are rated for output power. I cringe every time someone says they can't understand why their Yaesu FL-1200 won't make any more than 800 watts output when it is rated for 1200 watts. That is 1200 watts INPUT and it will make about 600 watt OUTPUT so their 800 watts is driving the crap out of an amp that they expect even more out of.
     
    KD2GOE and Shadetree Mechanic like this.
  12. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    As for a tuner between the driver and the amp.....you should not need it. The SB220 has a tuned input and should present an SWR of 1.5:1 or thereabouts. I wonder if the person that suggested that idea was thinking that the amp did NOT have a tuned input. Many of the older amps of that era or earlier did not have tuned inputs and back then pretty much all radios had tube finals which did not need a perfect SWR so the tuned inputs on amps were not really needed until solid state drivers came into play.
     
    Shadetree Mechanic likes this.
  13. 552fl

    552fl Active Member

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    No offense taken but I Am a cber .. somebody on the radio the other night was saying that's how they ran their sb220.. I'm always willing to learn something is why I'm on this forum. I purchase a bird meter and installed the pep kit in it. Was just trying to figure out the wattage to Drive the sb220 with the right way... Everyone has a different Theory on this
     
  14. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    Don't hit the amp with more than 100 watts peak and that should be fine. If you want to run it on AM I suggest you follow the info presented in post #6 of this thread. AM is high duty cycle and that amp's power supply was never designed for severe duty cycle like AM at full output. It will overheat and too as the fan cannot remove that kind of heat.
     
  15. 552fl

    552fl Active Member

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    thank you sir, for all your help.
     

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