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Microphone A/B Switch

Discussion in 'Home Brew' started by Atlasta, Jun 12, 2011.

  1. Atlasta

    Atlasta Well-Known Member

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    Hi all:

    Has anyone ever seen or built an A/B switch for two mics? It's a real drag switching between the D-104 and Super Sidekick when going from AM to SSB.

    Must it even have a switch? Can I build a simply 'Y' adaptor from two mic jacks (input) and one plug (output)? As long as both mics aren't keyed at the same time everything should be fine, yes?

    Yeah I'm new to home brew and this seems like a simple place to start.

    Advice, ideas or links please!



    Thanks
     

  2. unit_399

    unit_399 EL CAPO

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    Atlasta-


    Yes, you can use a simple "Y" adaptor to couple the 2 mikes to the radio, as long as the radio you're using (like your 135) has "relay" switching. This won't work on a radio that has electronic switching.

    - 399
     
    #2 unit_399, Jun 12, 2011
    Last edited: Jun 12, 2011
  3. Robb

    Robb Yup

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    Then again; why do you need two mics hooked up?
    Surely, there is a radio operator that you talk to on a regular basis that can tell you which mic sounds better. Of course, that may depend if you are using the on SSB or AM. But then again, I never had a D104 or a Turner sound bad on either AM or SSB. Either mic sounds great on either mode to me - IMO . . .
     
    #3 Robb, Jun 12, 2011
    Last edited: Jun 12, 2011
  4. kevin IB/379 Stringbean

    kevin IB/379 Stringbean Active Member

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    Heres what you are looking for.scroll down until you see the box with 3 mic plug ins in one box and one comming out to put in your radio.not cheap but its what your looking for.(Redmancb.com) under microphones.

    RedmanCB.com - CB Radio Equipment and Supplies
     
  5. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    It also may not work well with the two audio leads connected together. The output of one audio amp feeding into the output circuit of the other mike's audio amp is not a good idea. There is no isolation and the frequency response will surely suffer.It can be done using resistors to isolate the two microphones but you will loose signal level however you may have enough gain to compensate for that.You must also consider the output impedance of the two microphones being connected together.I wouldn't recommend simply connecting the two with a Y adapter.
     
  6. unit_399

    unit_399 EL CAPO

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    I believe the the amplifier output in both of the mikes he is using is disconnected by the keyup switch when they're in receive mode. :unsure:
     
  7. Atlasta

    Atlasta Well-Known Member

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    Thanks all!

    @Robb: On-air reports indicate that the audio is better on AM with the D-104 and better on SSB with the Turner, that's why I switch between them.

    @ Stringbean: That is almost exactly what I am looking for but yeah, it's a bit pricey.

    @Captain Kilowatt: I had wondered about the audio leads being tied together and possibly feeding back through the unused mic.

    I'll try making the Y adapter first... what's the worst that could happen? (Famous Last Words!)

    Thanks again!
     
  8. pro151

    pro151 KB4RMA

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    If Redman is building his box correctly you can also use it in reverse and use 1 Mic on multiple radios to keep the bench clear of multiple Mics. :D
     
  9. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    Perhaps it is but that would have to be confirmed first. I have seen the D-104 wired for VOX operation and powered from the radio itself so it may have had the audio lead rewired as well as the power lead.

    The audio won't feedback through the unused mic and be heard as the amplifier in the mic will not pass the audio in the opposite direction but it could lead to unwanted audio quality if the two mics are not isolated in some manner.Poor frequency is the most often result.
     
  10. Superidgit

    Superidgit Active Member

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    Ok yall know im a noob so i am saying this as a noob.

    With a "Y" connector and a power mic is it not possible to transfer energy into the mic thats not being used?

    Would it be like really bad SWR? Signals being reflected that we dont want to.
     

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