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astatic D104 to icom 718 mic pinout

Discussion in 'Microphones, Speakers & Audio Processing' started by N9DON, Feb 11, 2011.

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  1. N9DON

    N9DON Ham Member

    I'm sure this hasbeen asked a 100 times.Whatn wires from the amplified d104 go to the icom 718 mic connector? I want to doit right and make her sound good. Thank you:confused:
     
  2. NG6R

    NG6R XML Subscriber

  3. KD8GFC

    KD8GFC Ham Member

    If your D-104 has the six wire mic cord it will wire to the 718 as follows. 1-White 2-N/C 3-N/C 4-N/C 5-Red 6-Blue 7-Shield 8-N/C
     
  4. W9GB

    W9GB Ham Member

    Yes, just in the past 4 weeks.

    Questions about wiring up an Astatic D-104 microphone (Lollipop) to a radio is definitely a Top 10 FAQ.
    The disadvantages of crystal mic elements originally used in the D-104 are why you don't see their wide spread usage today.
    Replacement crystal mic elements are available from Kobitone (sold by Mouser).

    In addition, the majority don't know or understand that the simple elecret mic element sold at Radio Shack for less than $5
    sounds just as good, works very well with Icom radios, and can be installed in ANY older/legacy microphone or a DIY creation !

    w9gb
     
  5. W9GB

    W9GB Ham Member

    IF you have a D104 with a G stand, that does not have a pre-amp, then Tom, W8JI has a simple FET pre-amp that
    will perform the required impedance conversion from Hi-Z (crystal mic element) to the Lo-Z required by your Icom radio.

    His circuit has the added advantage for Icom radios, that you can eliminate the battery and power the pre-amp from the Icom (using R7 and removing battery)
    http://www.w8ji.com/d104_to_low_impedance.htm

    w9gb
     
  6. N9DON

    N9DON Ham Member

    In fact the D104 does have an amplified cicuit in the base(9v batt) so if I leave pin #2 open so the icom dc doesn't get to the astatic circuit,I should be o.k.? I put the white wire on pin#1, sheild on pin#7,red wire to pin #5 and finally the blue(blk) to pin#6 Am I on track?
     
  7. W9GB

    W9GB Ham Member

    G4WPW - Microphone Connections - Global Reference Site
    http://homepage.ntlworld.com/rg4wpw/date.html

    So, your D104 is a modern model (UG8 base??) with a pre-amp in its base.
    Astatic Schematics and Wiring Diagrams
    http://www.barovelli.com/projects/radio/radioastatic.htm

    Astatic T-UG8-D104 microphone manual and schematic (circa 1977)
    http://www.radioamateur.eu/schemi/acc_microphone/Astatic_T-UG8-D104_user.pdf

    The + 8 V DC (pin 2) from your Icom IC-718 transceiver is used to power the pre-amp in the Icom SM-20 or SM-30 microphones.
    Your Astatic D-104 microphone uses a 9 V battery in its base to power its pre-amp (1960s/1970s design).

    Again, Icom uses elecret mic elements in their factory microphones (hand and desk).
    Elecret elements require DC to function.
    The DC power on PIN 1 (Microphone +), referred to as Phantom Power, are for those Icom factory elecret microphones.

    Bob Heil covers this (educational) under his TIPS - All Things Icom, under DC De-coupling on Icom Rigs section.
    http://www.heilsound.com/amateur/tips/all_icom.htm

    The pre-amp circuitry in your D104 and other non-Icom desk microphones usually provides that de-coupling circuitry --
    BUT you are dealing with USED microphones -- with an UNKNOWN history of modifications and repairs.
    http://www.thiecom.de/ftp/astatic/d104_schematic.pdf
    So, you should perform a visual inspection of your mic versus the Astatic factory manual to determine what you actually have.

    w9gb
     
    Last edited: Feb 12, 2011
  8. N9DON

    N9DON Ham Member

    w9gb thank you for the schematic referances . It is a T-UG8 base ,I followed the wires in the base and they orespond to the schematic.Still unsure if it will be o.k. wired-pin 1-white,pin 7 shield, pin5 red, pin6 blue ,After reading all the notes and articles I'm more concerned with it making smoke .Any reasurance appreciated.Everyone has been very patient with my many questions.Thank you
     
  9. KE3WD

    KE3WD Ham Member

    When using the amplified '104 into a modern rig like the '718 and in SSB mode, start out with the gain pot under the bottom of the mic turned fully counterclockwise and then just "crack" it open just enough to get good ALC readings on the rig. Otherwise you are very likely to overdrive the AF section and in Sideband that will simply be a mess of unintelligible crap at the other end.

    And I really don't like the sound of the 104 in such applications, the mic that came with the 718 may not look so awesome as the 104, but it really does sound better.

    73
     
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