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Clean Signals from C Class!!!

Discussion in 'General CB Services Discussion' started by 15minigrass, Feb 24, 2012.

  1. 15minigrass

    15minigrass Active Member

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    If you run a clean un-modded/clean radio thru an AB amplifier to a C class splatter box, will the signal still sound splattered coming out of the C class amp?



    Just some thoughts I had!! 1-5.
     
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  2. GnG8d

    GnG8d Well-Known Member

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    Think about that for a minute .....


    Sent from my iPhone using Tapatalk
     
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  3. RatsoW8

    RatsoW8 Supporting Member

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    If the answer were "no" then why all the talk about dirty amps? I guess we'd be discussing splatterbox radios.
     
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  4. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

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    The weakest link is always the limits of the system. The class C amp is the weakest link. The fact that there is an ab box in front of it means nothing. If there was no ab amp and just the radio feeding the class C box it would be the same. Class C is not meant for an amplitude modulated signal.
     
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  5. GLR

    GLR Keeping It Good Natured

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    Seriously?
     
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  6. unit_399

    unit_399 EL CAPO

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    My understanding is that Class C amps work ok on am but not on SSb.
     
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  7. HomerBB

    HomerBB Well-Known Member

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    :D

    And about the original question, I have been told otherwise . . . That is, that the output sounds clean in such an arrangement. But hearing is so subjective and selective. Just ask my wife.
     
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  8. KM3F

    KM3F Active Member

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    This is what happens when conduction angle is not known about or understood.
    The term 'Linear' cannot be applied to a class C biased amplifier.
    Set to Class C, an amplifier will never amplify making the output signal a clean 'linear' copy of the input signal on SSB and likely not very well on AM.
    For linear opertion, the bias has to be somewhere between class A, AB1, AB2, not B or C.
    On FM or CW it does not apply for different reasons.
    It's the lack of theory and understanding what these bias setting mean is why the question keeps coming up.
     
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  9. 9C1Driver

    9C1Driver Well-Known Member

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    They work on AM and you can add a delay and even run them on SSB, depends on how you define "works". A class C box will "work" on SSB but it will sound crunchy and harsh. Ok for the part time sidebander.

    They do work on AM and continue to sell, that's why Davemade, X-Force, and fatboy stay in business just to name 3 builders. One reason for this is they are illegal and un-regulated, so people that want more power buy what they can get.

    The post above pretty much says it all though. Class C is not linear, and was not intended for AM or SSB use.
     
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  10. n0zna

    n0zna W9WDX Amateur Radio Club Member

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    you put a dirty

    signal in,you get a very dirty signal out.Get a good amp and a clean radio you dont have a problem.73 de JW
     
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  11. mackmobile43

    mackmobile43 Jock Supporter

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  12. IDIeselman

    IDIeselman Active Member

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    Why is it that most tend to piss and moan about A, B or C bias? Reality is the components they are recieving the signal on are not near the quality it would take to discern the difference? I agree it's clearly notable on proper equipment but, listening through a $6.00 speaker you will never hear the difference.
     
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  13. avistar23

    avistar23 Active Member

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    So your completely ignoring the fact that the non linear operation, and splattering harmonics bleeding into other frequencies, among many other problems, and while ignoring this, you feel it cant be heard? a 60 cent speaker can hear this. Bias is there for a reason, or linear operation, among other factors, i suppose, seeing as most people feel filtering isn't necessary either, and robs watts from their meter, why bias the thing anyway.

    Thats the same set of people that feel a single 2879 can produce 200 bird watts.
     
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  14. Moleculo

    Moleculo Administrator Staff Member

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    To the OP:

    How do you think the PA transistors in your radio are biased? If you understand that taking clean RF from a clean radio and inputting it into an improperly design amp will result in a dirty signal, why would it make any difference if you inserted an additional PA stage in the middle?

    I can hear it on a $0.99 speaker if that amplifier is putting out a ridiculous amount of harmonics on a band that I happened to be tuned to...which is where the problem is. Avistar23 nailed this one. I have experienced this and it's really easy to reproduce / demonstrate the problem.
     
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  15. HomerBB

    HomerBB Well-Known Member

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    Moleculo, are you saying that the only place it is detectable is on a harmonic frequency?
    Additionally, what equipment is it detectable on if on the same frequency?
    I am assuming equipment sufficient to hear it is Amateur transceivers, correct?

    Serious questions, not arguments.

    Homer
     
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