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Thread: 3.5mm jack -> XLR??

  1. #1
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    Default 3.5mm jack -> XLR??

    Hey guys. A while ago, I made a cable converting a stereo 3.5mm jack -> XLR.

    It works, but the audio is distorted. Does anyone know how you are supposed to wire jack -> XLR for minimal distortion?

    I understand that XLR is balanced, but jack is not, so how do you wire it to fix that prob?


    Cheers,
    Dan

  2. #2
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    XLR is just a connector, you can wire it many different ways, one of which is balanced.

    What are you trying to do exactly? Go from 3.5mm jack to XLR, or the other way round?

    If you want to go out of a 3.5mm jack to XLR and preserve the stereo then you need to go to 2 XLR's - one for left, one for right. These will not be balanced, but balanced is only really neccessary if you're going any significant distance (>10m). You could wire to a single XLR using the common ground and pin 2 - left and pin 3 - right but at some point you'll need to break out to stereo connectors unless you have equipment that takes stereo on an XLR (not very common in my experience)

    I suspect what you've done is wired pin1 grnd, pin2 left and pin3 right, then plugged that into a socket expecting a balanced signal. The kit is then subtracting one from the other to reduce the noise and coming up with what is essentially the difference between left and right - hence the distortion!

    http://en.wikipedia.org/wiki/Balanced_audio

  3. #3
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    Quote Originally Posted by norty303 View Post
    I suspect what you've done is wired pin1 grnd, pin2 left and pin3 right, then plugged that into a socket expecting a balanced signal. The kit is then subtracting one from the other to reduce the noise and coming up with what is essentially the difference between left and right - hence the distortion!

    http://en.wikipedia.org/wiki/Balanced_audio
    HA! thats pretty much exactly what I did!

    Although, when I did that, I found it on a diagram on the internet, so yeah.

    Right now, I don't have the resources to make 2 cables, so i'll just have to live with mono (Which shouldnt be too bad anyway)

    And yes, the cable itself is only short, but the cable connects to a port in the wall, which could run halfway around the auditorium for all we know.

  4. #4
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    Is it just a single XLR on the wall or a pair?

    How does it come out the other end and what does it connect into?

    I have worked places where they take a stereo output from a mixer, wire it into a single XLR (the same way you've done it) run that through a single cable to the amp room where they have a tail on it that breaks it back to a pair of connectors to go into the crossover or whatever. Works ok and saves an extra cable however its very situation specific (e.g. that install)

    If you are just using one side of a pair of sockets (mono), then my recommendation is to wire both left and right to the hot pin to ensure you get both signals, it's just it won't be balanced.

    I'm guessing this is so you can plug your iPod into a house PA? If so, I'd advocate buying one of those 3.5mm to pair of RCA adaptors and going via a mixer of some sort that has balanced XLR outs, most DJ mixers have them nowadays. As you say, you can't be sure of the distance that cable is running, or whether it's routed alongside some noisy mains cable. It also means you don't have to run the ipod output so hard, which don't exactly have great distortion figures anyway.

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