JM+2U vs. M+2U Turner...what's the diff.?

Discussion in 'Microphones, Speakers & Audio Processing' started by K0UC, Dec 24, 2009.

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  1. K0UC

    K0UC Ham Member QRZ Page

    What's the difference between these 2 mikes?

    I think they had JM+3U and M+3U as well.

    And some without the "U" on the end....

    Any comments on how well any of them work? Great, I'm sure.
    Turner generally makes good stuff and you can't go wrong.

  2. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I think it's just the way the PTT switch is wired up: M+2 wired for relay switched rigs, JM+2 for electronic (solid state) switched rigs.

    The mikes themselves, and their internal preamps, are identical I believe.
  3. KD8DEY

    KD8DEY Subscriber QRZ Page

    I'm not sure BUT I think the 3's had compression?
  4. W9GB

    W9GB Ham Member QRZ Page

    The "M" designates the microphone as a "mobile mike".

    Steve, WB2WIK/6 is correct (good memory) about differences in the Internal wiring of the Turner microphones.
    The M+2/U has wiring for RELAY switching, while the JM+2/U has wiring for ELECTRONIC Switching.
    See Turner Wiring Booklet -- below.

    1976 advertisement for the M+2/U
    Ceramic cartridge, controllable gain (pre-amp)

    The M+3 model added speech compression, as a feature.
    Another 1976 advertisement for the M+3

    Turner M+2U & JM+2U Schematic

    Turner M+2 Assembly Pictorial

    Eric Braun's Turner microphone story

    Turner Wiring Booklet Mic Wiring.pdf

    History by Tom Moss, who worked at Turner, 1952 to Close (1979)
    Over one million of the 350C mobile microphones were sold!

    Telex purchased Turner from Conrac Corporation and closed the Cedar Rapids plant in 1979.
    By end of the 1980s -- most of the Turner designs from the 1970s were eliminated
    from the Telex product catalog.

    Last edited: Dec 25, 2009
  5. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    And the preamplified mikes were mostly used by CBers who wanted to sit back two feet away from the mike to talk on the radio.:p

    They weren't great, they were actually kind of silly.

    When you get that far away from a mike it never sounds good.
  6. AA9WE

    AA9WE Ham Member QRZ Page

    As already posted, difference between them is Electronic, and relay switching. Different radios required different switching method. Either mic can be made opposite switching. Details for changing in the manual.
  7. AE5TE

    AE5TE Ham Member QRZ Page

    Way back in those days I had a Turner M+3 and I guess it worked OK - if nothing else they were louder than stock mics. How much of that was speaking voice vs. background noise (or in channel vs. splatter) is the question, and depended a lot on how one chose to operate.

    Even their so-called noise cancelling mics (the Road King series) turned the background noise into a god-awful howling/screeching noise if you set the gain high enough. And of course everybody ran at 11 on a scale of 1-10, to try and hit 'em with that extra pound or two.

    But the Turner "Power Mikes" were a CB thing FTMP - folks could get that "special" sound without screwdrivering a rig.

    I dunno - can you even buy those funky 7V mercury batteries anymore?
  8. K0UC

    K0UC Ham Member QRZ Page


    Thanks for all the replies! anything...use in moderation. They are CB mikes...though the compressed ones might be OK on HF SSB if properly adjusted.

    It's not a mobile mic, but I used to run a Turner SuperSideKick on my HW-100, properly adjusted for excellent audio.

    And the batteries...probably not too convenient...espeically these days with prices so high on specialty batteries.

    Thanks again....Merry Christmas. I doubt I'll find a JM+2U under the tree, but I can hope! I'm just remembering seeing them in the catalogs when I was a kid. And thinking about them again as I collect some CB gear from the 23 Channel days.

  9. W9GB

    W9GB Ham Member QRZ Page

    The Astatic D104M6 and some Turner models used the 7 volt silver-mercury cell.
    These are no longer manufactured due to the mercury content / enviromental disposal issues.

    The 2 most popular adaptations are:

    1. Use a 9-volt battery as a repalcement for the 7 volt battery cell.

    2. Power the microphone from the +8 volts available
    Check current limit (mA) from radio - usually from 10 to 100 mA to handle the microphone's pre-amp.
    Most 8-pin microhpne connectors on VHF/UHF radios have power on a separate pin ---
    these pin configurations are NOT standardized by the mfg. --
    SO a microphone wired for a Kenwood, will not work for Yaesu, Icom, etc.

    Last edited: Dec 25, 2009
  10. AA9WE

    AA9WE Ham Member QRZ Page

    Actually the batteries are still made, get them from most any battery store, Ebay, or do what I do and use 5 watch type batteries in a stack, tape, or some heat shrinkable material works well to make one.
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