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Can I plug in an additional cabinet when an amp is on?

Discussion in 'Amps and Cabs [BG]' started by Dan Pomykalski, Nov 7, 2018.

  1. What does the lifespan of a switch have anything to do with my original question or the response you’re replying to? The response you’re replying to was concise, relevant, and answered the question. Re: thinking about this way too hard.

    And switches are under $5 for a Carling... tubes and amps are considerably more...
  2. The difference between my post with a pronoun as the subject and your post with a pronoun is that my pronoun could only logically be referring to one thing. Your post with a pronoun could have been referring to two...
  3. How ‘bout a counter offer?
    I’m out of here. Deal?
    Dan Pomykalski likes this.
  4. BadExample


    Jan 21, 2016
    Oh, Jesus. Take it outside ladies.
  5. xnewyorka

    xnewyorka Supporting Member

    Jun 26, 2006
    NYC Area
    OK, final answer:

    You should turn your input gain to zero, turn your master volume to zero, and unplug your instrument cable.
    Then you can feel free to plug and unplug your speaker cable. The risk of hurting something is pretty much zero at that point.

    I can't see any possible way to short from tip to sleeve while in the process of plugging in or unplugging a 1/4" plug. The plug tip does not make contact with the contact arm until the plug is 90% of the way in, and by that time, the tip is nowhere near anything that is grounded, so creating a short is impossible.

    Not sure why nobody has mentioned this important caveat:

    But by all means, make sure the _other_ end of the speaker cable is already plugged into the other cabinet before you connect it to your amp or to your live cabinet.
    Otherwise, the tip on THAT plug, which will be "live", could come into contact with ground, which would NOT be a good thing. Also, the tip could get shorted to ground while plugging it in, depending on how the jack is constructed in the other cabinet.
    Last edited: Nov 7, 2018
  6. I'll just go ahead and point out that even if it WAS possible to short the output, this isn't a problem for a tube amp. They don't like OPEN circuits. In fact some tube amps have self-shorting speaker jacks precisely to prevent damage in case you forget to plug in (but this obviously doesn't help at the cabinet end of the cable lol..)
    xnewyorka likes this.
  7. Nightman

    Nightman If it ain't low, it's got to go! Supporting Member

    Jun 3, 2013
    Atlanta, GA
    An interesting thread, for sure!
    agedhorse likes this.
  8. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    As a general note, it is entirely possible to short the tip to the sleeve at the load end of the cable when plugging in. The sleeve on some jacks is long enough to bridge the tip to sleeve on the jack. We design in protection on solid state amps specifically for this condition in the event that the cabinet is not SpeakOn equipped.

    (Yes, I am aware that it's usually not a problem with tube amps)
  9. Huh! I suppose jacks are made that way to provide mechanical stability. Hadn't thought of that.
  10. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Some jacks use extended metal barrels and some use reinforced engineering plastic with spring metal inserts.
    HolmeBass and David Jayne like this.
  11. gidbass

    gidbass Supporting Member

    Aug 5, 2009
    I wouldn't, but it's your amp/head...;)

    Good Luck!
  12. xnewyorka

    xnewyorka Supporting Member

    Jun 26, 2006
    NYC Area
    Good point - thanks Andy. I have updated the wording in my **IMPORTANT** note above. Please let me know if it is factually correct as written, or if I should revise it further, and I will update it to make it completely accurate. I could also add a comment that this is more of a concern for solid state amps, if you feel that's appropriate.
  13. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    I wanted to clarify this for folks who may refer to this thread in the future. Many have a difficulty understanding how this my apply to a solid state amp, or that there is a difference.
  14. Kukulkan61

    Kukulkan61 Supporting Member

    Feb 8, 2011
    Northern Arizona
  15. nilorius


    Oct 27, 2016
    Riga - Latvia
    The best you should do before is, turning the amp off and then connect the other cab. I don't think it's hard to do so.
  16. I’d weigh the cost of smoking the amp vs the cost of a smoking a tube, should a failure occur. Then be ready to Man up and get out the plastic. Or after thinking about it, were it I. Well then, I’d just turn the dam amp off and swap cables. Also I’d probably search to see if someone has already done the comparison here on tb. More often than not they have.
    BadExample and Plectrum72 like this.
  17. baxter_x


    Nov 27, 2013
    I did plug some cabs while my amp was on. However it was muted and I did it pretty rapidly to avoid any shortage with jack cables. Nothing wrong with that.
    But I try to avoid it as much as possible.

    However it happened a wrong thing one doing so. The end of the jack got in contact with a metal plate on the ground. It produced little sparks and the fan of my svt 4 pro suddenly got into the revs. I immediately switched off everything, waited a several minutes and switched it back on. I probably reacted fast enough, no damage to the amp. That's the reason why I tend to use speakon cables as much as I can now.
    Interesting thread though.
    Dan Pomykalski likes this.
  18. primusfan1989


    Jan 17, 2005
    new jersey
    If you do it when the amp is on standby you'll be fine, I wouldn't recommend doing that when the amp off stand by
  19. When you got sparks, were you adding a cab to an amp that already had as cab, or adding a cab to an amp with no cab?
  20. He started it :sour:
    BadExample likes this.

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