I need a 5 pin/wire cable/jack combination - HELP

Discussion in 'The Projects Forum' started by icydash, Jun 29, 2011.

  1. icydash

    Thread Starter Active Member

    Jan 14, 2009
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    Hey guys! So I'm trying to decide what cable / connectors to use for a project and could use some help.

    Basically, I have to get the following from one PCB to another PCB, stationed a few feet away:
    9v DC, DC GND, an audio signal, AC GND, and a control signal (+5v DC or 0v DC when in "off" state).

    As you can see, there are five signals basically that I have to carry from one board to another. I'm trying to find the smallest, cheapest, and most readily accessible jack and cable combination to do the job.

    I was thinking about using a MIDI cable/jacks, as it has 5 or 6 (I can't remember) pins/wires. However, midi jacks are kind of big for the small box I want to put it all in.

    The circuit will be used in a recording studio, so major points go to anyone who uses anything readily found in a studio as the cable, like some way of doing XLR, or 1/4 inch cables, MIDI, etc.

    Thanks!!
     
  2. KJ6EAD

    Senior Member

    Apr 30, 2011
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    You could use two or three ⅛" or ¼" phone connectors and cables. The AC signal needs a shielded cable anyway. If you're not concerned about the AC signal being degraded, you could use a 5-pin mini DIN connector like you see on some power supplies and old computer keyboards. MIDI uses a 5-pin DIN (full size).
     
    Last edited: Jun 29, 2011
  3. wayneh

    Expert

    Sep 9, 2010
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    3,038
    You probably don't want to hear this, but I recommend two cables: One shielded for the audio and, say, an ethernet cable for the DC stuff.
     
  4. icydash

    Thread Starter Active Member

    Jan 14, 2009
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    Thanks a lot guys for your responses. I'd prefer one cable, but if two separate cables are better, than so be it. I'm just up for any great suggestions!

    Realistically, though, how much would the signal be degraded if i just used a MIDI cable? What is causing the degradation ?
     
  5. KJ6EAD

    Senior Member

    Apr 30, 2011
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    The amount of trouble you get using a MIDI cable would depend on several variables including other electrical noise sources and how the cable is routed in use. A MIDI cable is unshielded and running an audio signal through an unshielded cable will allow the signal to pick up AC hum from the wiring in the building as well as electrical noise from any other equipment nearby including fluorescent lights and computers, sometimes even AM radio stations. You would also be hearing a click or pop in your audio from the switching transient every time that DC control voltage was turned on or off.
     
  6. icydash

    Thread Starter Active Member

    Jan 14, 2009
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    Crap. Good to know. Thanks.
     
  7. icydash

    Thread Starter Active Member

    Jan 14, 2009
    81
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    What about a telephone jack / wire? That has like 4-5 wires right? And it's made for audio ?
     
  8. KJ6EAD

    Senior Member

    Apr 30, 2011
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    Telephone cables are unshielded twisted pairs. They carry very compressed audio. If your audio is below 3kHz, that would work but you'd still get the switching transients.
     
  9. icydash

    Thread Starter Active Member

    Jan 14, 2009
    81
    0
    So it sounds like the best bet is going to be using one 1/4in or 1/8in connection for the audio, and then something else, like an ethernet cable, or MIDI cable, or whatever, for the remaining 3 lines of DC stuff. Thanks so much to everyone who responded; this was incredibly helpful.
     
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