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Bright flash of light from PA Horn - What!?!

Discussion in 'Amps and Cabs [BG]' started by wisconsindead, Mar 31, 2015.

  1. So at rehearsal last night my band mate was messing with the PA to adjust vocals and tapped the 25 db pad which caused an insanely loud high frequency burst that about dropped me to the ground. However at that moment I saw a flash of light come from the horn of one of our Peavey PA speaker cabs. Anyone know what that could be? They seem to work fine still but I would've thought that the horn just fried up right there an then. My drummer said hes seen that before as well.

  2. bholder

    bholder Affable Sociopath Supporting Member

    Sep 2, 2001
    central NY state
    Received a gift from Sire* (see sig)
    What kind of horn is it? Doesn't sound good, is the horn actually still working?
  3. Probably a lightbulb type horn protector.
    wave rider, Jim Carr, danosix and 4 others like this.
  4. Jazz Ad

    Jazz Ad Mi la ré sol Supporting Member

    Yes, it's typical way to avoid burning coils.
    It also mean you need to at least use a limiter or stop running your PA so hard.
  5. jeffmaxwell

    jeffmaxwell Commercial User

    Oct 8, 2007
    San Diego, CA
    owner, Silver Hammer Designs
    Peavey uses an incandescent lamp as part of the high frequency protection circuit in their crossovers. The flash of light was just the protection circuit activating to save the horn driver. Normal operation if you send an insanely loud high frequency burst to the speaker. Lots of manufacturers use a similar design.
  6. Marial

    Marial weapons-grade plum

    Apr 8, 2011
    Yep, this used to happen with an Eden 410 cab I had. At the time I had no idea what it meant, but it was COOL, DUDE. Later, I found out why it was lighting up and was embarrassed once again. That band was so loud, and I was so loud, Bill Batson told me to unplug one of my cabs because he couldn't mix around the bass the last time I played the 7th St Entry in Minneapolis. Tardish.
    TMARK likes this.
  7. My guitarist managed get his PA cabs to activate the protector one night, and has been convinced that the speakers are blown ever since. Never mind that we've been using it for months and it sounds fine, and I've attempted to explain how the light bulb protector works...

    I've given up, but I'll ask for the "blown" cabinets when he eventually replaces them :)
    wisconsindead likes this.
  8. Interesting! Thanks guys!
  9. Jim Carr

    Jim Carr Dr. Jim Gold Supporting Member

    Jan 21, 2006
    Denton, TX or Kailua, HI
    fEARful Kool-Aid dispensing liberal academic card-carrying union member Musicians Local 72-147
    SWR golliath II 410 cabs used the same type light bulb horn protection. Gelb music in Redwood City, CA used to stock them. I think it was an automotive dome light bulb. $3.50 in 2001. :D
  10. I will note that it hurt like a BITCH when that signal came through :eek:
    S-Bigbottom and Bugeyed Earl like this.

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