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SILVER STREAK 150 (2 X MRF455) ?

Discussion in 'General CB Services Discussion' started by Switch Kit, Mar 31, 2008.

  1. Switch Kit

    Switch Kit Active Member

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    What is it about these little amps ? IM sure I've had 1/2 a dozen of these things over a few decades it would seem. (They work ! :)and whomever builds them ,IM guessing they have been building them for a long time)Seems like 1 watt DK usually does the trick on these little guys. IM getting to my question , (without using a cap resistor mod or not) Will use a 1 to 4 watt pep at 100% modualtion into this little guy . My numbers are ballpark 20 to say 60 audio watts on low (I could whistle 80 but that don't count) , 80 to say 120 audio watts on high (I could whistle 160 watts but that don't count either) . On just about anyone of these boxes I've had over the years they always seem to DK bigger numbers then I would expect on the high side of these little guys , IM guessing this is normal for these ? Keeping in mind, IM only talking about a 1 watt drive ? 80 seems like alot ? or is it just the way the box is built ? Thanks
    [​IMG]
    [​IMG]


     
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  2. Switch Kit

    Switch Kit Active Member

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    30 views and no clue ? hmmm
     
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  3. mackmobile43

    mackmobile43 Jock Supporter

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    The mrf455's are meerly 60 watt transistors so anything over 120 or so is fluff.

    Data sheets don't lie, http://datasheets.foxdelta.com/mrf455.pdf
     
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  4. Switch Kit

    Switch Kit Active Member

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    My question is why the high DKs on these with only 1 watt , the many I've had over the years all acted that way. Your data sheet means nothing to me unless you explain it ? why the high DK's on these little boxes at 1 watt compared to many others is the question. As far as fluff goes , I already said that didn't count. No offence to you Mack , but folks tend to ask simple questions (or look for simple answers) and I could drop a data sheet on somebody any day of the week weather i understood it or not ....kind of like this past thread ......http://www.worldwidedx.com/showthread.php?t=29016 Thanks for the reply all the same Mack , the data sheet doesn't tell me why these little amps key higher then I personally would think they would on the high side of a 2 x 455 amp. I can believe the low side at 20 to 60 but 80 to 120 audio pep seems strange to me ? Is when a radio is perfectly tuned at 1 to 4 into this box , what happens to the 4 to 1 ratio from the box , this is why I "think" 80 watt DK would be high on this one ? NO ?
     
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    Last edited: Apr 3, 2008
  5. freecell

    freecell BANNED

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    simply compare the 455 to another popular 60W transistor to answer your ?.

    http://www.firecommunications.com/trdbase/2sc2290.pdf
    2SC2290....1 in 20 out, 13db., 12.5vdc @ 28mhz.
    Ref: Po - Pi Graph, end page.
    db = 10LOG(Pout/Pin)
    db = 10LOG(20/1)
    db = 10LOG(20)
    db = 10(1.301)
    db = 13.010

    http://www.firecommunications.com/trdbase/mrf455rev0.pdf
    Ref: Po - Pi Graph, mid page.
    MRF455.....1 in 50 out, 17db., 12.5vdc @ 30mhz.
    db = 10LOG(Pout/Pin)
    db = 10LOG(50/1)
    db = 10LOG(50)
    db = 10(1.698)
    db = 16.989

    the increased gain of the 455 allows it to produce (2.5X) more power output with the same amount of drive at the lower input levels.. the information is in the spec. sheets.

    also, if we move both devices to 27mhz. the gain of both increase still further, the gain of the 455 increasing even still more than the 2290.

    the Silver Streak 150 is an extremely drive sensitive Class C Amplifier.
     
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    Last edited: Apr 3, 2008
  6. fnkycoldmedina

    fnkycoldmedina Well-Known Member

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    hey freecell whats the specs on the 2879?just curious to see the gain on those.
     
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  8. Switch Kit

    Switch Kit Active Member

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    the increased gain of the 455 allows it to produce (2.5X) more power output with the same amount of drive at the lower input levels.. the information is in the spec. sheets.

    also, if we move both devices to 27mhz. the gain of both increase still further, the gain of the 455 increasing even still more than the 2290.

    the Silver Streak 150 is an extremely drive sensitive Class C Amplifier.


    That would explain the higher DK's on the high side on these with such a low input into them , thank you Freecell .
     
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  9. mackmobile43

    mackmobile43 Jock Supporter

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    And it might have something to do with them big ole resistors feeding the rf into the input tranfomer which would probably vary from unit to unit.


    Neat little box anyhow, I'll give you $40 for it and I won't tell anyone how bad you beat me.(y)
     
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    Last edited: Apr 5, 2008
  10. Switch Kit

    Switch Kit Active Member

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    I was thinking more along the lines of 75.00 shipped Priority but haven't got there as of yet. Damned near mint condition as is. I sure appreciate the info on this one all the same. I was just surprised on why these little dudes produced such a healthy DK on the high side. My personal 4 x MRF454 box keys a little over 100 with a slightly over 400 watt swing , although I finally was able to see one of those XL 500s 4 x 1446s damned near swing 500 the other day (fluff or no fluff !) , blew me away ! This past year or so , between MOSFETS and the 1446 transistor , both have been impressive for what little knowledge I have on either , I really like those 1446s , they really seem to have some big balls on the 11 meter band ! As far as this little Silver Streak goes , the builder must have done well for himself , I remember these little guys from the mid -80s and there still selling them. I also remember a lot of the amps back then carrying Motorola Transistors more so, then the Toshiba's I see today ? I've heard cost had something to do with it nowadays.
     
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  11. mackmobile43

    mackmobile43 Jock Supporter

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    nice little box for sure
     
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  12. JK_RUBICON

    JK_RUBICON Registered User

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  13. Gearhead

    Gearhead Member

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    I've got one of those silver streak 150s right here, that I fixed for a local girl (needed a new so-239). It seems like I can set up the radio to run it on either low or high. If I set the dk to run the box on low, then I get 120 watt dk on high. If I set the dk low enough, to run on high, then I get almost nothing on low. I got the best results on low, so I might just tell her to run it on low only. (still does over 100 on low)
     
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  14. Switch Kit

    Switch Kit Active Member

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    I still say 1 watt drive on these is best to go . Isn't a linear more linear when they key higher on high with less swing from there ? I was always under the impression that anything keying lower then 1/2 watt on AM could mess with the radios audio quality ? even still , cap/resistors will do that scope wise anyway , IM thinking class C AM is what it is ? You can run your amp any way you please (I prefer to run them lightly rather then hard) , My numbers with a 1 watt to 4 drive from radio looked very comfortable as far as longavity might be concerned in numbers given ? 1 watt to 20 pep was pushing 80 to 200 on high audio were the low side was doing 20 to 80 on audio. But I can understand where Gearhead is coming from by saying running it on low looked best , let me guess GH ? was that with about a 2 to 3 watt drive on the low side ? I can't believe they put 4 watt max input on the back of these . What's really going on here Freecell ?
     
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  15. Beetle

    Beetle Well-Known Member

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    A Class C amplifier is not linear regardless of how much or how little drive, or how much or how little swing. By definition, Class C (and Class B) amplifiers are NOT linear.
     
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: mrf455's

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