Scott 312(A) vs 4312

Discussion in 'Tuners' started by rmp, Jan 8, 2019.

  1. rmp

    rmp New Member

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    These contemporaneous tuners have the same front end, but the 4312 has more controls. What is the essential design difference? I assume the 4312 has a more sophisticated IF section. Is that true? Can one hear a difference?
     

     

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  2. Punker X

    Punker X Moderator Moderator Subscriber

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    Tried to compare scats, but not finding much on the 312A
     
  3. rmp

    rmp New Member

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    I think the IF section of the 312(A) is pretty much the same as that of the 312C or the LT-112B, the service manuals of which are online. For the 4312, the schematic is online, but I don't have the knowledge to discern any important difference(s).



    Are people paying 10 times as much for a 4312 merely for extra front-panel controls?
     
  4. rocket_no9

    rocket_no9 New Member

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    Location:
    West of Boston
    i have a 4312 downstairs that sounded glorious till one side went out ... fired it up last week and both sides were out. doh.
    if it's any help i have paperwork that'd come w/ tuner.
     
  5. 39cross

    39cross AK Subscriber Subscriber

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    Last edited: Jan 10, 2019
  6. Punker X

    Punker X Moderator Moderator Subscriber

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    Quickly searching and comparing this morning. Both have 3 stage IF. 4312 has a differential amplifier with feedback / AGC before the detector. The LT112 does not have. 112 scat has a block for the MPX which may be differ. Rest seems pretty close. Not enough time this morning to lookup the LT112 MPX circuit to see if there are differences.
     

     

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  7. 39cross

    39cross AK Subscriber Subscriber

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    Doing a quick visual check, my 312A has 5 germanium transistors in the MPX section, the 4312 looks like it has 8 if I read the schematic correctly. The 4312 overall looks much more sophisticated, as you'd expect.
     
  8. KiM3Ce

    KiM3Ce AK Subscriber Subscriber

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    If I recall correctly, the 4312 has a Nuvistor front end.
     

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  9. rmp

    rmp New Member

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  10. rmp

    rmp New Member

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    Over at the Yahoo FM tuners forum, someone has reported that the 4312 is unusual in having 2 notch filters.


    I am getting the impression that whatever superiority the 4312 has to the 312(A) is because of several differences that are, individually, relatively minor.
     
  11. rmp

    rmp New Member

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  12. Bob@FM

    Bob@FM Active Member

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    Location:
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    below is a good summary of the specs and features differences. Interesting, the capture ratio on the 4312 is much lower. Meaning it may have a different detector design.
    But I see little difference between the 2 models in overall design and specs, just that the 4312 does minor things a little bit better. It may have used selected parts to achieve that.

    It needs to be stated also that later 312 versions (312B, 312C, etc) were very different from the first original version shown below. Later ones used FETs instead of Nuvistors.

    [​IMG]
     

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