microphone switch box

Discussion in 'Homebrew and Kit Projects' started by KD5JBK, Oct 7, 2008.

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  1. KD5JBK

    KD5JBK Ham Member QRZ Page

    Hey all. I have a question for the masses. I want to simplify all the clutter around my micro shack as far as mics and speakers go. I have one mike that I would like to use for all my rigs. The problem is that all my mfj rigs state that the mic and PTT must be cut when in recieve but my ts-120s says that the PTT must be a separate switch.(wired like a regular mic) To complicate things all the mfj rigs are 5 pin dins while the 120s is a 4 pin. The MFJ rigs are the 9402 and the 9406 radios. Is there an easy way to bring these all together? Wadda ya all think?

    Chauncey Baker
  2. K1LLR

    K1LLR Premium Subscriber QRZ Page


    stay away from mfj..all my experiences have been bad..mfj makes a box to switch mics/radios,,bought one from hro and it didnt work..opened it up and there was not a single jumper anywhere,,hro happily refunded my money,you can only talk on one mic at a time so choose one and use it..keep it simple.:p:)
    Last edited: Oct 26, 2008
  3. N0EQ

    N0EQ Ham Member QRZ Page

    I'm a little confused in terminology. "Cut when in receive"
    "Separate switch" "regular mic" doesn't really describe
    what's going on in the circuit.

    Can you be a little more specific and/or post a schematic?

    Craig 'Lumpy' Lemke
  4. K9YLI

    K9YLI Ham Member QRZ Page

    for planning you will need

    cables and plugs to fit each rig mic socket.
    a box to mount the stuff in

    a socket to fit the mic you want to use.

    biggest problem is the switching circuit as you may have to adjust impedance and or volumn of the mic element.

    most PTT circuits are a simple contact to ground.
    bringing in the power for electret mic you have to be sure you isolate
    each rig cable from the others so as not to accidently common two voltage
    sources together...
  5. K9STH

    K9STH Ham Member QRZ Page

    I used to use a switch to change the microphone among various rigs. However, that seemed to cause problems with some of them. So, I went to a minibox with RCA phono connectors which then were wired to each individual rig but retained a switch to move the push-to-talk among the various units. I wired the push-to-talk with 2 jacks in parallel so that I can use either the button on the microphone or a foot pedal to activate the transmitters.

    All that I have to do to move the microphone is to move an RCA plug to the appropriate jack and then move the switch to that transmitter.

    I have been using this arrangement for a number of years and that has worked out very well.

    Glen, K9STH
  6. KD5JBK

    KD5JBK Ham Member QRZ Page

    i haven't figgured out how to post schemes yet but if you go here:


    and refer to page three it shows how the microphone element and the PTT is switched. The ts-120s doesn't need need the microphone switched off on recieve like the mfj.(I am really bad at explaining things sometimes)

    hope this helps

  7. KE7VZW

    KE7VZW Ham Member QRZ Page

    perhaps a patch panel ?
  8. KL7AJ

    KL7AJ Ham Member QRZ Page

    I was thinking the same thing. Plenty of these coming out of the dungeons now that lots of A.M. broadcast stations are digitizing their audio chains. Get a GOOD balanced jackfield for nothing....looks cool, too. :)
  9. W4SUL

    W4SUL Ham Member QRZ Page

    I use the NCS Multi switcher for my multiple radios and mic/soundcard/keyer etc. it's a bit pricey but really does the job well, and I like having seperate mic gain controls for each device.

  10. M3TPH

    M3TPH Ham Member QRZ Page


    i have same problem, many outputs from radio to Pc for digi modes and from PC to radio (send digi) and of course, i want to pipe audio from rig to other line level devices etc.

    I figured i would build a small multichannel mixer then use small gain op-amp to make good any losses in the mixer stage. I will also incorporate vu leds on each channel and this is not as expensive as you may think. I will also use isolating transformers from old hi speed internal modems to provide complete audio path isolation.

    search google for 6 channel mixer or microphone mixer, some schematics are available to get you off to a flying start.

    have fun,
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