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Best place to get an amp?

Discussion in 'Amplifiers' started by Limeybastard, Aug 7, 2017.

  1. 543_Dallas

    543_Dallas
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    You will need an external switch (foot pedal) to put it in transmit mode on any band. You can wire a relay into your mic cord that will key the amp when you key the radio. This is the better way to key an amp than how cb amps are made. It doesn't hot switch the relay and no chattering issues with a ssb delay.

    There are many ways to key the amp and it's not complicated. All HF amps will be like this unless some hack puts in an RF sniffer type keying circuit.

    Ameritron uses a 12 volt circuit for the relay. Heathkits and other old amps might have 120v or more. This is something to keep in the back of your mind.

    Don't expect much of a warranty on a cb amp. No one will warranty transistors and you're buying an illegal product anyway. It is a buyer beware market. If you want a 500 watt amp buy one that will do 1000 and run it at 500. Being cheap will catch up to you.


     

  2. undertaker

    undertaker
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    If you have a good antenna system you don't need an amp. I have one but never use it.
     
    Tallman likes this.
  3. Tallman

    Tallman
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    Same here. I have a bunch of amps here that are left overs from a company that would not pay their bills. I have a Yaesu FL-2100 that has never been connected to an antenna since I have owned it. It was part of a package deal with a Yaesu FT-890.
     
  4. Limeybastard

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    I get you, get an amp with some headroom for reliablity reasons. Im all for that.

    I guess most of these tnt and xforce amps and some Texas Star ones dont have a variable setting, Im assuming the output is based soley on the input from the driver?
    As an example the 955HP Stryker min approx dead key is I think 5W upto 20W deadkey. Leaving it on the 5W deadkey would be most beneficial for reliablity purposes. What would the "swing" be with that 5W on a 4 or 6 "pill" xforce / tnt no driver amp approx?
     
  5. Limeybastard

    Limeybastard
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    For those who have experience with the texas star 1600 model. Would it be a better choice to run this at lets say less than half power output compared to running the 500V at near wide open? I was thinking running the sweet 16 at tops 600W pep? Plus the benefit being id probably still be able to use my existing 75A PSU?
     
  6. 543_Dallas

    543_Dallas
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    There's no need for a variable if you have a radio with variable power. With larger amps like a 4 or 6 pill the typical variable used in cb amps can cause more issues than it's worth.

    The 955 should be a good match for a straight 4 pill. No driver needed. You need to be concerned with power out of the amplifier to avoid smoke.

    For Toshiba 2879s I would tell you to run the 4 pill at 125 watts deadkey max and let it swing to 500 or 600 pep. With the new transistors I would do what xforce recommends and keep the deadkey at 100 or less. For pep with the new pills I would stay around 400 to 500 pep and hope for the best.

    On a side note I would not run the 955 at higher than 10 watts deadkey. There was some odd waveform distortion on the one I had when ran above 10 watts deadkey. I suspect the finals are making all the clean power they can at that point. You would be able to run the 955 at these lower power levels with the 4 pill. It will take less than 10 watts deadkey and 40 to 50 watts pep is more than enough to hit the 500 watt mark. I'm basing this off of a class C 4 pill. With the amp being biased the drive requirements may be a bit lower.

    Just my 2 cents. Everyone does it differently.
     
  7. 543_Dallas

    543_Dallas
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    I don't use mine often but when I need it it's there.
     
  8. Limeybastard

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    !
    Cheers, your advice above is in reference to dei based straight 4 pills right? The texas star is a 500variable model, could one just "ignore" the variable knob, or will its existence interfere?
    What were your thoughts on headroom? Power wise. Hence my question about the sweet 16 or a straight 6 pill TNT which is also on my shortlist.
     
  9. dave457

    dave457
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    Instead of that texas star, try bm technologies
     
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  10. 543_Dallas

    543_Dallas
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    All of my amps have Toshiba transistors in them. I had a 1 pill tnt with a dei2290 that failed for no good reason so I never bought any more Chinese transistors.


    When I was using 2878s on the base where headroom was a concern I was running them at 60 pep per pill. Look at the spec sheet and you will see IMD is lowest at this power level. Back in the mobile days when toshibas were cheap I beat on them hard.

    That makes a 4 pill a 240 watt amp, an 8 pill a 480 watt amp. Low drive can be an issue with a poorly designed amplifier. I've saw them oscillate at low drive levels.
     
  11. Limeybastard

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    Last paragraph, my same thoughts. This is exactly what i thought.
     
  12. Limeybastard

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    Anyone heard of Hopper amps?
    Looks alright,uses HG transistors. Whats pp100 transistors? I think xforce uses them now, think I'll pass. Plus their massive wait times and all.
     
    #27 Limeybastard, Aug 8, 2017
    Last edited: Aug 8, 2017
  13. Road Squawker

    Road Squawker
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    That's not what an "exciter" means, an exciter is what you would probably call a "driver",.......... AKA: radio
     
  14. jon666

    jon666
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    i have several amps never needed them. my 100 watt kenwood does the job.
     
  15. Limeybastard

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    I eagerly await your for sale posts then. ;-)
     

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