IC 7300 & D-104

Discussion in 'Microphones, Speakers & Audio Processing' started by AF6CO, Mar 24, 2019.

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  1. AF6CO

    AF6CO XML Subscriber QRZ Page

    I have a D-104 That I bought new back in the mid 1980's that I've never used. I was going to use the D-104 with my FT 897 but I never got around to buying the tool to wire the plug for the 897. The 897 went belly up and I now have a brand spanking new 7300. I've got the Heil low to hi Z transformer sitting in a box somewhere.

    I'm wondering what this mic would sound like on the 7300 with the original mic cartridge, or should I just get the kit from Heil and install it into the D-104. I also think that I read somewhere that I'll need a capacitor to isolate the +8 volts on the audio line.

    So what do the experts think?
  2. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    "Tinny and loud" :)

    The D-104 is a great mic on a HI-Z boatanchor transmitter for which it was designed (I have a couple of them for my old AM rigs). But probably not the best on a 7300 IMO.

    The hand mic that the 7300 comes with does SURPRISINGLY well. Super punchy and I have received really good audio reports

    But hey - try it and see what you think. You've got all the bits you need - no sense not trying it out and maybe work with a local ham friend to see how he thinks it sounds

    WA8FOZ likes this.
  3. KM6XP

    KM6XP Ham Member QRZ Page

    There is a guy on eBay that sell pre-made short patch cords that will go Cobra 4 pin to ICom 8 pin and it has the cap added. The great thing is you don’t have to alter to D104 to use it. I have a couple of the patch cords a 6” and a 2”, $15.00.

    I like the old mics, just such a cool vibe, I have a couple d104 mics and turner SSK mics, they work great for SSB.

    Try it out.
  4. AF6CO

    AF6CO XML Subscriber QRZ Page

    I have the adapter cable to use my Pro 7 headset. I'm thinking of just putting a phono plug on the mic and using the adapter cable.
  5. W5LZ

    W5LZ Ham Member QRZ Page

    If you have to have that D-104 Mic then I would replace the element with one your radio "expects". Otherwise, forget it.
  6. K6LPM

    K6LPM Ham Member QRZ Page

    The 7300 works just fine with numerous dynamic Mic's as well as condenser Mic's. You do not need to cap it either. The power is on a separate pin. You need only wire the gnd, the audio and ptt. I have used many different mics including gaming headsets, cell phone headsets with condensers and dynamic Mic's such as the Heil elite gold and shure sm 57 . All if them have given me great unsolicited signal reports. I expect a d104 to be just as well as anything.
    I also add that the stock hand mic also sound very good and has also had unsolicited compliments as well.
    WD8T likes this.
  7. G0GSR

    G0GSR Ham Member QRZ Page

    There is indeed 8v on a separate pin but the Mic (Pin 1) also has a DC bias for the electret so should be blocked for use with a dynamic mic.
    It is however current limited to about 8mA so would do no damage but is best removed.

    NG0L likes this.
  8. K6LPM

    K6LPM Ham Member QRZ Page

    I thought that you had to cross the audio pin with the power pin together to get the power to the electret condenser ?
  9. G0GSR

    G0GSR Ham Member QRZ Page

    That is already done inside the transceiver. There are volts on Pin 1 fed via an internal 1k resistor from the 8v rail.


    Last edited: Mar 26, 2019
  10. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Depends on the D-104.

    The original D-104 is just the microphone "head" which contains a crystal, very high-Z element. The D-104C was the same but contained a ceramic transducer.

    The rest of the mike (stand, PTT bar, etc) is not a "D-104," it's an accessory. Many of them manufactured after 1970 or so contained a battery-powered preamp in the stand (at the base) which converts to a higher voltage at a lower impedance and that preamplified "D-104" can drive just about anything. But the REAL D-104 is just the round microphone "head" and I'd be shocked if that could drive an IC-7300 by itself.

    Why not just try it and see what happens?

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