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Low-noise low-consumption IN/OUT line switcher

  1. Sep 18, 2012 #1
    Hi guys,

    I need some idea on how to realize a simple IN/OUT line switcher.

    The fact: a small room for meetings with amplified mixer, a PC with Skype, an human operator, people in the room and outside (via Skype).

    The use: a lecturer talks to people using a MIC and the PC drives the signal from the mixer to the net through Skype (conference call). Of course, those present at the meeting can follow the conference from the sound system.

    The needs: the operator uses a selector (switcher) to interact briefly with people connected in the conference call (i.e. to be sure about the quality of the transmission, to give service infos...), then he goes back to the lecturer. The operator uses headset with micro. Normally people from outside are not asked to be lecturers, only occasionally they can have an interaction to say few words after the invitation of the operator.

    The circuit must be supplied by a PC USB connector (5Vcc, low consumption), it should be capable to drive signals from/to IN/OUT, mixer and audio PC lines, MIC and headset without introducing distorsions or attenuation. The selection of "operator mode" can be done either by a single push-button or by a switch, with status LED required.

    Any idea is welcome!
  2. jcsd
  3. Sep 18, 2012 #2

    it is the time to refine my request :wink:

    I guess I need:

    - a simple buffer to separate the output signal from an audio board into two lines, one directed to the headset, the other directed to the preamp input. One could use one horrible audio Y-cable splitter, but I want to avoid any attenuation and/or source of extra noise.

    - a simple "audio deviator" to send the input signal to the audio board coming from the MIC (headset) OR from the preamp output. Here the same, low attenuation and robust noise rejection. I know people who do that by using a mechanical deviator...

    The main request is for low cost and low consumption.
    Do you know if there are some discret components for that? I would think a schematic based on OpAmps, but I don't know which model is available for single power line 5 Vcc max (USB)

    Thank you in advance for your help!
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