Non-popping condensor mic switcher
Old 5th May 2013
  #1
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Non-popping condensor mic switcher

Hi, i am new to the forum. I am trying to build a mic switcher that will work with phantom powered condensor mics. but my current builds are popping. i am using a DPDT stomp switch and I have tried combining all the grounds. didn't seem to make much difference. If you have any ideas i would love to hear them.
Old 5th May 2013
  #2
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Richard Crowley's Avatar
 

You will likely need to reveal exactly what you mean by "mic switcher". Likely you have something specific in mind. But there are so many kinds, it could take all week for us to guess what kind you are talking about.

Do you mean something that switches between several different microphones to a single input?
Do you mean something like a mute switch to turn a microphone on and off?
Old 5th May 2013
  #3
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i have two consensor mic i am want to be able to switch between on one channel. 2 mics in, 1 out.
Old 6th May 2013
  #4
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You would probably need a separate phantom power supply that is always connected to both mics. The switch would then only switch the audio to the mic pre input.
Old 6th May 2013
  #5
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Richard Crowley's Avatar
 

Or you could try a non-trivial scheme that runs the P48 power to both mics all the time, but only switches the AC signal (i.e. the audio). Or you could use scheme that momentarily mutes the audio output while switching microphones.

Neither of these can be done with a simple switch.
Old 6th May 2013
  #6
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i am trying to imagine a way to isolate the 48v from the line and add it back to the mics directly so they stay powered. i know you can you caps to block it somewhat. how would i go about isolating the 48v so i can still use it?
Old 6th May 2013
  #7
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mjrippe's Avatar
 

As I said earlier, you need an external +48v source. You can't use the one from the preamp unless you open it up and disconnect it from the input XLR and run it out of the preamp to your switch box. Even then, it might not have enough current available to run two mics at once.
Old 6th May 2013
  #8
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i guess ill try to design some sort of timer circuit that mute the channel first the makes the switch, then un-mutes it. I have never worked with timer before though. ill have to do some research.
Old 8th May 2013
  #9
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use an arduino micro and a relay board pretty easy to do that.
Old 8th May 2013
  #10
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Hi
To make a unit that truly switches 'silently' will take considerable effort as rather than 'switching' it needs to be a 'fast ramp' where the signal is attenuated over a few milliseconds rather than a 'cut' of a switch / relay.
Any 'hard' switch scheme will at least 'tick' or 'pop' slightly as you have the mic preamp gain amplifying any discontinuity or voltage difference. Even it this were 'silent' the sudden change of sound from the different mics / positioning would still be heard (psycho acoustic response to sudden changes of signal).
Getting phantom to both mics permanently and a 'simple' switch arrangement is probably the least bad possibility.
None of these schemes would need a 'micro' and indeed introducing HF noise source next to mic level signals is a recipe for yet more 'interference'.
Matt S
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