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  1. #1
    Z28 is offline Radio Operator Home Channel: 6,15,17,20
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    Default Equal power output, # of pills and amp draw question.

    Has anyone tested this?

    For example, go for a fixed deadkey output of 200 watts. Drive the amp to what ever it takes to get that power. Do this for a 2 pill, 4 pill and an 8 pill and see how much more current is needed for the larger amp.

    The assumption is that the larger amp, for example a 2x8 will need more amps to do 200 watts, versus say a 1x4, all else being equal.

    What good is this test? To find the sweet spot in current draw efficiency. I've noticed running a bigger amp and cruising it has a much more cleaner output than driving the piss out of a smaller amp. The may be a similar thing. Results may be interesting.

    I see the natural tendancy is to get the most out of your amp. "Man, I'm getting 1100 bird out of my 8 pill" etc. versus crusing a 16 pill at 750 bird but not even heatin up the box. Putting out clean, linear output that is really in true range of the 2sc2879's spec before major harmonics kick in.

    I don't know, just things to think about.
    Orange County, CA. Youtube id = z28radio.

  2. #2
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    750 BIRD out of a 16 pill? won't underdriving electronics cause problems?

  3. #3
    Crusher's Avatar
    Crusher is offline Pro Mauldropper DX Numbers: 2190 Home Channel: the trax
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    Quote Originally Posted by Z28 View Post
    Has anyone tested this?

    For example, go for a fixed deadkey output of 200 watts. Drive the amp to what ever it takes to get that power. Do this for a 2 pill, 4 pill and an 8 pill and see how much more current is needed for the larger amp.

    The assumption is that the larger amp, for example a 2x8 will need more amps to do 200 watts, versus say a 1x4, all else being equal.

    What good is this test? To find the sweet spot in current draw efficiency. I've noticed running a bigger amp and cruising it has a much more cleaner output than driving the piss out of a smaller amp. The may be a similar thing. Results may be interesting.

    I see the natural tendancy is to get the most out of your amp. "Man, I'm getting 1100 bird out of my 8 pill" etc. versus crusing a 16 pill at 750 bird but not even heatin up the box. Putting out clean, linear output that is really in true range of the 2sc2879's spec before major harmonics kick in.

    I don't know, just things to think about.
    That is how an amp is suppose to be run, but either some amp builders try making the extra buck telling people what there box will do and and people think they can run it like that all the time. Or someone told someone that told someone etc............ and now it has become a popular myth that you should DK your box as high as possible. I see guys all the time around here DKing a 4 pill at 500-700+ watts and run it like that all the time. They think this is OK. When they don't even know what a 2879 or a 2290 or a 1446 is rated at. They just know what someone said and now it should be so.

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    Quote Originally Posted by junkie 870 View Post
    750 BIRD out of a 16 pill? won't underdriving electronics cause problems?
    why?

    I use a 2 pill to make 60 avg, my 8 does 400 avg. works fine

    Hated for being the postman of truth

  5. #5
    Big r 184 Guest

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    Pills are rated on a 12 volt system . At 16 or 18 or 20 volts don,t these ratings change. At 15 volts on a 2879 i run 100 watts per pill on my last box in line 8 or 16 pill . At 20 volts 200 watts per pill. It works for me.

  6. #6
    prometheus's Avatar
    prometheus is offline Peanut Gallery Member DX Numbers: ifvg Home Channel: 19834672876594
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    Quote Originally Posted by Big r 184 View Post
    Pills are rated on a 12 volt system . At 16 or 18 or 20 volts don,t these ratings change. At 15 volts on a 2879 i run 100 watts per pill on my last box in line 8 or 16 pill . At 20 volts 200 watts per pill. It works for me.
    how's the audio?

  7. #7
    Big r 184 Guest

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    I get nothing but good reports on audio. I,m using a uniden 78 elite 1+4 into a 16 pill.

  8. #8
    Crusher's Avatar
    Crusher is offline Pro Mauldropper DX Numbers: 2190 Home Channel: the trax
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    LOL, don't forget what Motorola would call MTBF (Mean Time Before Failure). Yes you can drive it harder, overvolt it to 20 volts and do what you want. What you do not realize, that when doing this and causing pills to heat up quicker, you have what they call metal migration and added stress that will start to destroy the ballast resistors on the emitters. It's your box and you do what you want. But I like to have the same pills in a box 15 years later and not have to replace them yet. Now keydown or something that is different and it has to be worthwhile. But for everyday use, lower DK and let er go. To each their own.

  9. #9
    Crusher's Avatar
    Crusher is offline Pro Mauldropper DX Numbers: 2190 Home Channel: the trax
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    Quote Originally Posted by Big r 184 View Post
    Pills are rated on a 12 volt system . At 16 or 18 or 20 volts don,t these ratings change. At 15 volts on a 2879 i run 100 watts per pill on my last box in line 8 or 16 pill . At 20 volts 200 watts per pill. It works for me.
    Get Toshiba's Datasheet and see what they say. By the way, the increase in output power is because the RF voltage is about twice the DC. Meaning at 12 volts DC RF signal will be about 24. When running 20 volts DC, RF voltage is around 40. These are only approximate/guestimates. Also take into account Temperature ratings/current/voltage and then down the line SWR. All of this comes into play. I'm just ranting now cause I get tired of people trying to run a 4 pill at 700-1000 watts DK everday and wonders why they have problems.

  10. #10
    coolbreeze is offline Pro Mauldropper DX Numbers: 38 Home Channel: 19 where else
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    crusher I can run my 4 pill at 1000 dk at 16-17 volts and it sounds great. but your right, the average amp, depending on what size transformers and such does come into the equations. but thats really a different post from his original post.

    you are 100% correct on the amp draw.
    loafing an amp can sund better, depending on how its run.

  11. #11
    Mr. 557 Guest

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    At nominal levels, I use the 100 watt per 2879 in the final amp rule. If its an 8-pill, then I expect 800RMS, 12 pill- 1200RMS, so forth. Biggest problem with people involved in cb radio is the obsession with watts! Slam a 2x6 into a 16 and talk 2500-3000RMS all day and slam some idiot 15 miles away on the other side of town while getting your thrills for a worthless cause, meanwhile digging into your pocket deeper and reaching for the credit cards to fix equipment sooner because of sheer stupidity while the more experienced are enjoying the first dx in 3 months while you sit on the sideline wishing you were there-
    More watts will always take last place to proper setup!

  12. #12
    Crusher's Avatar
    Crusher is offline Pro Mauldropper DX Numbers: 2190 Home Channel: the trax
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    Quote Originally Posted by Mr. 557 View Post
    At nominal levels, I use the 100 watt per 2879 in the final amp rule. If its an 8-pill, then I expect 800RMS, 12 pill- 1200RMS, so forth. Biggest problem with people involved in cb radio is the obsession with watts! Slam a 2x6 into a 16 and talk 2500-3000RMS all day and slam some idiot 15 miles away on the other side of town while getting your thrills for a worthless cause, meanwhile digging into your pocket deeper and reaching for the credit cards to fix equipment sooner because of sheer stupidity while the more experienced are enjoying the first dx in 3 months while you sit on the sideline wishing you were there-
    More watts will always take last place to proper setup!
    Exactly, like I tell everyone I deal with. "You want big numbers, get a big box, don't use a little box and run it like a big box". Unless you have money to spare, then throw it my way. LOL

  13. #13
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    Quote Originally Posted by Crusher View Post
    Exactly, like I tell everyone I deal with. "You want big numbers, get a big box, don't use a little box and run it like a big box". Unless you have money to spare, then throw it my way. LOL



    This is one of the most accurate, truthful, realistic post in this whole thread

    Hated for being the postman of truth

  14. #14
    Big r 184 Guest

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    Hey 557 you got it right in my opinion 100 watts per 2879 at 15 or 16 volts. Back in the 1980s the real davemade crew told me to run like that 20 volts 200 watts per 2879 for keydowns . Ride around or skip i run my 16 pill at1600 with forward swing on my bird 10 watts reflect .I,ve had my 16 pill for 9 yrs burned 1 pill because whip came loose in ant.

  15. #15
    Big r 184 Guest

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    I think some of you guys took what i said about 200 watts at 20 volts the wrong way . Thats for comp only key downs . You won,t last long talking on 20 volts allday. Although i have a friend 923 who keys a 8 pill skull cracka at 400 watts 20 volts with a 200 amp MMaul . Hes been runing like that for about a yr now and never blown up sounds real nice too. I would not recomend trying this.

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