How To Adapt a Microphone System to a Rig

Discussion in 'Microphones, Speakers & Audio Processing' started by N6TDG, Dec 8, 2019.

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  1. N6TDG

    N6TDG Ham Member QRZ Page

    Hello all,

    I have microphones that I use in another line of work as Voice of the Fair. So I have a MXL Broadcasters Microphone (Dynamic) that I plug into a Behringer USB mixing board and into my Macbook Pro for recording.

    So my question is, how can I adapt such a microphone, (or any microphone for that matter) to plug into an Icom 751. I imagine that an adapter from the mixing board to the icom 8 pin plug. I would also guess that somewhere along that particular line would be a sort of PTT switch or button.

    Be forewarned, I am not too technical, but after repeated beatings with a 2x4, this ol mule sometimes gets the idea.

    I see that everyone raves about Heil micrphones, but frankly, there are others I would like to use, I just want to know how to do it.

    As for the mixing board. It is not important for me to actually put more lows or highs in my voice. Over processing my voice is something that I usually avoid in production anyway.

    Thanks in advance for any help for this ol guy getting into amateur radio later in life.

    Oh and the Icom 751 is a radio that was gifted to me as my first HF rig. I have built a DX Commander Multi-Band Fan Vertical and getting ready to set that up once the rains subside. I did replace the memory board with a Piexx one here recently and getting anxious to turn everything on and clear out the dust!

    Once again, thanks
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The mixing board needn't be used for mixing or frequency equalization: To use it with a ham rig, its primary function would be to simply provide the right output level to drive the transmitter's mike input stage.

    To this end, it should work fine.

    Yes, you'll need a properly wired cable from the Behringer to the Icom. If you do a Google search on microphone cables for amateur radio transceivers you'll find vendors who sell these pre-wired and ready to go, and they can be a good deal since soldering to the tiny pins in those mike connectors can be a challenge without the right tools, a magnifier and steady hands.:p

    The early-gen Icoms were designed to be used with biased condenser mikes and provide bias voltage at the connector for that. If using a dynamic mike, or the Behringer, you'd want to not use that bias (phantom voltage for condenser mikes is normally provided by the Behringer, if you need that -- with a dynamic mike, you don't need it and that voltage can actually damage the mike) so a blocking non-polar capacitor is often used. But the "pre-wired" cables configured specifically for the early-gen Icoms should have that all taken care of.
  3. N6TDG

    N6TDG Ham Member QRZ Page

    I do have a big tube condensor mic, also MXL,(770?) but I try and stay away from condensors as they tend to pick up way too much room noise. That is why I moved to Dynamic. If in a nice sound proof studio, the condensors are great... But if I went to the condensor, then the behringer board would provide the phantom power for the microphone. I suppose then, I would use a cable that goes from the three pin XLR to the Icom 8 pin mic input.
    I would guess somewhere in between a box or switch for PTT would be installed?

    Believe it or not, my condensor is so sensitive, I can hear bees buzzing and the flowers growing with the headphones on...

    Thanks for the info. Time to hit the interwebs and see what kind of cable I will need.
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Condenser mikes have some serious advantages, but one is they're really inexpensive to make (the cartridge). The "housing and cable" cost way more than the active element.

    For amateur radio, I'd avoid them also.
  5. N6TDG

    N6TDG Ham Member QRZ Page

    Well, for the money, I like the MXL Broadcasters mic, around $170 through Amazon. It is dynamic. There is another microphone that I would like to try, its a Harlan Hogan microphone which is designed for Voice Over work. But for now, I will stick with the MXL. Although I would like the Shure 7...sigh
    KW6LA likes this.
  6. N6TDG

    N6TDG Ham Member QRZ Page

    I am currently checking out the proper cables. I think I will need to write the sellers to ensure I get the proper cable for my particular use. Thanks for the help
  7. KF4ZGZ

    KF4ZGZ Ham Member QRZ Page

    For the limited bandwidth capability of a ham radio, a cheap Radio Shack or similar vocal mic (RS 33-3038 etc.) will work as or better than any thing.
    If you already have the MXL, go for it .... other wise the high dollar mics are wasted money ....IMHO.
    Using the mixing board going to the radio can also cause issues, but we'll wait until they show up. ;)
  8. KM3F

    KM3F Ham Member QRZ Page

    My question is, why try different mikes if your not interested in shaping the audio with your mixer?
    More expensive buying mikes for audio satisfaction than shaping the audio with the equipment you have.
    Many wide frequency response mikes will tend to hit the Low'a pretty hard.
    For that you need to attenuate below 150 hertz.
    The radio shack or Behringer XM8500 at $20 will work very well but may still need some low end attenuation.
    There is very little difference between these two mikes except the xm8500 has a shock mounted cartridge..
    Good luck.
    KW6LA likes this.
  9. WA3GWK

    WA3GWK XML Subscriber QRZ Page

    I use an inexpensive Shure dynamic mic with my ICOM IC 9100. I purchased a Heil adapter cable that connects to the 8 pin round connector on the rig and terminates with two connections, one to plug in a PTT or foot switch and the other a 3 pin XLR for the mic. The cable incorporates a capacitor to block the voltage that would normally be required for a condenser mic. The 9100 accommodates the lower output of the dynamic. Other folks report good results with similar dynamic mics such as the XM8500 with the appropriate connecting cable. Good luck!
  10. KE0ZU

    KE0ZU Ham Member QRZ Page

    Doesn't matter how much you pay for your whizbang mic thats "flat" from 20 cycles to 12 KC, or how, and or what you use to process it's output, that 2.7 KC slice your crystal filter lets through your radio, is all thats going out over the airwaves. So if you want to play with how you sound, you don't have much to play with.

    Now if you have a Phasing type sideband transmitter.....
    WN1MB likes this.

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