Icom 738 mixer/mic wiring sugestions

Discussion in 'Microphones, Speakers & Audio Processing' started by VE1QET, Jan 25, 2019.

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  1. VE1QET

    VE1QET Ham Member QRZ Page

    Hello folks,
    Newbie here with an oldie but goodie radio.

    I have an alesis mixer and a few cradioid mics laying around that I want to try an incorporate into my station. I tried looking for info on wiring a connection from mixer to radio with no luck. All I found was using a condensee mic direct to use a decoupler in series on the mic lead.
    I callled Icom and all they told me to download thr manual snd thr pinout is in the book.
    I assume it is the same pinout as the ic718 and 735 but cant be sure.
    I want to got from mic to mixer to radio. Can someone give me some reference here. Thanks in advance.

  2. VE3TMT

    VE3TMT XML Subscriber QRZ Page

    Ditch the mixer, get a Behringer XM8500 mic and wire directly to mic jack. Great mic. Taking the chance of introducing RF in your mic audio using the mixer. Pin 8 is mic audio, pin 7 mic ground.
  3. K4EM

    K4EM XML Subscriber QRZ Page

    I agree, ditch the mixer. The mixer mic output is line level you'll fry your radio. If you need something like that try a UR6QW; EQ, preamp device I have one works great with my IC7300.
  4. WE4E

    WE4E Premium Subscriber QRZ Page

    Well you won't fry your radio, but you need one more component. The output of your mixer is line level, likely +4dbu, and your radio is mic level, likely more like -30dbu or so. You'll need at a minimum, a level match network to reduce the output of the mixer to something that's in range for your radio. If you don't, you'll almost certainly distort the input stages of the mic preamp, and the mic level knob won't go to the left far enough to fix that.

    You can use something as simple as a resistor "t-pad" to do the job. Google that, there are online calculators that will help you find the values. You'll likely also have to unbalance the output of the mixer, which is a simple wiring thing. You may get away with just that. You may need an isolation transformer and/or perhaps some small ferrite cores in case it picks up a little rf.

    That all sounds more complicated than it really is, but some assembly required.

    Or cheat and buy a W2IHY i-Box.

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