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Bad Cables...

Discussion in 'Safety' started by AVGuyAndy, May 3, 2005.

  1. AVGuyAndy

    AVGuyAndy Active Member

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    So I'm loading in my sound gear. I get my board set up, snake pulled, all that good stuff. Then I try to attach my gear to the school's FOH PA. They have a Mackie Powered Mixer. There's 2 amp inputs, so I need to split my mono XLR signal into 2 1/4 lines. I took a new Y-cable, out of the package, and plugged it in. Nothing worked. I went through different cables, snake cables, since I assumed that Y-cable was good, since it was brand new. Turns out it was dead. So I had to dig up my older Y-cable. It worked great. Hooray for new cables which don't work!

    Just had to get that out, lol. BTW, Crown PCC160s rule!
     
  2. Mayhem

    Mayhem Senior Team Emeritus Premium Member

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    Hope that you kept the receipt and are returning it.

    Have had several IEC leads come straight out of the box and either have Active and Neutral crossed over, or no continuity on the Ground. Not sure if it is a problem with the heat moulding process but these get tested as soon as they come through the door.

    I guess that quality control goes out the door when cost cutting is a priority.
     
  3. AVGuyAndy

    AVGuyAndy Active Member

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    Nah, The cable (in box) has been in the department forever. Finally found a use for it. So I'm guessing the receipt is long gone. I didn't buy it anyway :p
     
  4. ship

    ship Senior Team Emeritus Premium Member

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    Good reason both never to trust new or should we say assume (Ass out of you an me) gear. Also never to pull gear for a show without testing it.

    Got in some Soca to Edison fan-out adaptors today. Not only did I meter the pins to ensure it was wired for 120 instead of 208v, but I also took apart a sampling of the plugs to ensure the correct conductor went to the proper terminal. One can never tell who besides you in building your gear knows what they are doing in building it for you. Just because it comes from a distributer, does not mean someone building it for your order knew what they were doing. Hopefully they do but you need to verify still.

    In my case, they were using Hubble brand Commercial grade Edison cord mount receptacles on 12/3 SJ wire. The person that wired them did it properly up until the point he or she installed the strain relief. Note to all, a 16/3 SJ cord has a different outside diamater than that of a 12/3 SJ - much less SO cord. A strain relief on a plug is designed to grip any number of cable types and wire sizes within it. In other words, just because your strain relief will screw down further or all the way, does not mean you should. Hand tight plus some should be sufficient to grip the cable.

    This company in using the plugs already not well suited for 12ga wire, screwed the strain relief down all the way in now making a cable that's about 3/8" in dia. now about less than 1/4" in thickness under the clamp. Hmm, it's rubberized wire. Once under pressure, it would tend to stretch with the bulk of it moving out of the way. What's moving out of the way? The insulation coating the conductors and protecting it from shorting to each other. Cut a cross sectional area of a plug that's been over tightened in strain relief and at times you will see as little as 1/32" of rubber insulation between conductors. Given the wires flex and move about some, that's very easy to cut thru in causing a short.

    Point of this is that even if "professionally done" and wired properly, those making it at times don't know any better than a amature. Inspect what you get before you use it.
     
  5. BNBSound

    BNBSound Active Member

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    That's a big problem with the cheaper molded cables. I unwrapped a batch of TT patch cables for a studio once and 22 out of 100 were polarity reversed, another 6 didn't work at all. But hey, if you want cheap stuff they have to make it by the millions to get it out and still make money, so you have to expect some duds. Even at a 25% loss the guy was still farther ahead than if he had bought good ones.
     
  6. mbenonis

    mbenonis Wireless Guy Administrator Premium Member

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    You didn't mention how this was supposed to be wired - it's quite possible that the Y cable you ordered was wired incorrectly or was simply the wrong cable for the job. If you are attempting to split a mono XLR output into dual 1/4 (I assume TRS, tip-ring-sleeve, here, but you did not say), Pin 1 needs to be connected to the TRS connector's sleeve, pin 2 the tip, and pin 3 the ring on both TRS connectors. If it does not have a TRS connector for both 1/4 ends, but rather just a TS (tip-sleeve) connector, return the cable - it's not what you need.
     

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