Open or closed circuit? what's the diff?

Discussion in 'Luthier's Corner: Guitar & Bass Technical Discussi' started by ryan04, Oct 12, 2008.

  1. ryan04

    ryan04 Member

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    Hey guys, quick question. In my haste I bought a 2 conductor CLOSED circuit mono jack, is this ok to use in a guitar? And what's the difference between open and closed circuit mono jacks?

    thanks
     
  2. David Collins

    David Collins Member

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    I'm not entirely sure what a "2 conductor closed circuit mono jack" is to be honest. If it's a 2 pin, or two conductor (meaning 1 ground and 1 hot), then it can't really be called closed or open. In simplest terms, a closed circuit is a complete circuit and an open circuit is one with a break somewhere in the line.

    If you bought a switch jack, it may be labeled N.O. (Normally Open), or N.C. (Normally Closed), but it would have anywhere from 3 to 9 pins (or tabs), not 2 as you describe. I wonder if you may be describing something like a 4 pin NC switch jack, with 2 pins for the Normally Closed switch and to pins for the signal conductor (ground and hot).

    In any case, if you do have some sort of a switching jack it doesn't matter. If you're wiring a standard mono output, tip is tip and ground is ground no matter what else it contains.
     
  3. walterw

    walterw Gold Supporting Member

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    here's one.
    [​IMG]
    it shorts the hot & ground together when nothing's plugged into it, which is the sort of thing you want for an amp input jack as it keeps the amp silent when you pull the signal cable out of it.

    it should work fine for a guitar output.
     
  4. ryan04

    ryan04 Member

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    brilliant, that's exactly what it is. Thanks alot guys!
     
  5. Bob V

    Bob V Member

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    Um, actually that doesn't necessarily short the hot to ground unless you connect it that way. The swich can be used for lots of things. What it does is connect the hot to something else when you don't have a plug inserted (the larger part moves a little and disconnects it from the other lug). Guitars with two jacks, one stereo and one mono, would have one of these. Also, the tiny 1/8" / 3.55mm jacks are very common - they're in your stomp boxes. When you plug in a power tap it disconnects the battery.
     
  6. walterw

    walterw Gold Supporting Member

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    oops! (in best ed mcmahon voice),"you are correct, sir!"
     
  7. Bob V

    Bob V Member

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    It's an illusion that I work very hard to cultivate.
     

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