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Analog Multiplexing

  1. Apr 7, 2010 #1
    Hi everyone,

    I'm trying to take this circuit:


    and use an analog multiplexer to do the switching for me instead of the large, heavy, awkward, and expensive DPDT switches. Someone suggested a MAX4051 but I don't see how that could work, as I believe it is 8 to 1?

    I want to switch all 6 channels at the same time with one SPST switch. Is a multiplexer appropriate for this, or should I be looking at something else?

    Attached Files:

  2. jcsd
  3. Apr 7, 2010 #2
  4. Apr 7, 2010 #3
    I'm not sure I understand it. This allows me to input 6 channels and choose three of those to output simultaneously, correct? I have to output to 6 channels simultaneously.

    This is a more simplified version of the same circuit:

    I found the MAX4948, but I don't know anybody who has them in stock and I have no idea how to wire it o_O
  5. Apr 7, 2010 #4


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    Staff: Mentor

    A SPST switch switches one input signal between two possible output channels (DEMUX), or two input channels into one output channel (MUX). So it's not applicable to a 6-channel system.

    Do you want a 1:6 DEMUX or a 6:1 MUX function? Or do you just want to be able to drive 6 output channels simultaneously based on 1 input channel?
  6. Apr 7, 2010 #5
    I was inferring that I want to be able to switch the box with a single switch that drives a circuit (i.e. a toggle switch), not run the signals through the switch itself. Sorry for the ambiguity.

    Hmm. How do I explain? I can explain my real-world problem:

    I have a 6 channel sound system connected to my PC that I want to share with my 2 channel PS3.

    Hence, I am running 6 channels from my PC to the box.

    I am running 2 channels from the PS3 DEMUXed to 6 channels (3 for left, 3 for right)

    I am running 6 channels from the box to the amplifier.

    I want to be able to switch between my PC and the PS3.

    6 in from PC

    "6" in from PS3

    6 out to amplifier.
  7. Apr 7, 2010 #6


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    Staff: Mentor

    Just to clarify, there are 6 speakers, right? Those are the end customers of either 6 input audio channels, or 2 input audio channels? Relays would have higher audio quality compared to analog switches. Would you be okay using relays instead, controlled by one SPDT switch?
  8. Apr 7, 2010 #7
    6 speakers - 5.1 surround sound system. You've got the idea.

    Yes, I would be OK with that. And relays don't have to worry as much about negative voltage, do they?
  9. Apr 8, 2010 #8
    Are you thinking I should put 3 DPDT relays in parallel instead of 3 DPDT switches and control the voltage with a simple on-off SPST toggle switch?
  10. Apr 8, 2010 #9
  11. Apr 8, 2010 #10
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