Lightning in my Cab?

Discussion in 'Amps and Cabs [BG]' started by loudness, Dec 28, 2012.

  1. loudness


    Dec 28, 2012
    So I registered for the forums just to ask about this:

    Yesterday at practice I was messing around with my Steel Leather pedal. I also use a Bass Big Muff and a Boss ODB-3. When I put the Steel Leather pedal at the end of the chain, my cab (Ampeg 4x10 of some kind running off of an SWR SM-500), the speaker cones lit up. They weren't flickering, it was a slowly increasing glow, like a lightbulb turning on. It only happened when I was actually playing.

    I'm sure this can't be good for any of the parts involved, so I'd like a bit of advice:

    1) What is going on?
    2) Why?
    3) What can I do to stop it other than not putting the Steel Leather at the end of the chain, where I think it sounds best.

  2. eeyorebass


    Jan 2, 2008
    Sounds to me like your putting too much power to the tweeter and your lighting up the tweeter protection, literally.

    Ampeg uses an automotive type lightbulb instead of a fuse for their tweeter protection circuit. You send too much juice to the tweeter, and the excess energy lights up the bulb rather than blowing your tweeter.

    Try turning the tweeter down or cutting some highs at the amp.

  3. Yep. SWR cabs do the same thing. You must be ungodly loud.
  4. CL400Peavey

    CL400Peavey Supporting Member

    Nov 7, 2011
    Grand Rapids Michigan
    He may not really be that loud, but his pedal may be putting out a ton of signal at the right frequency to light up that bulb.
  5. Chef

    Chef Moderator Staff Member Supporting Member

    May 23, 2004
    Columbia MO
    Staff Reviewer; Bass Gear Magazine
    free light show!
  6. jlepre

    jlepre Supporting Member

    Nov 12, 2007
    Parsippany, NJ
    Yup that's it. All of the above
  7. OK, his TWEETER is ungodly loud.
  8. CL400Peavey

    CL400Peavey Supporting Member

    Nov 7, 2011
    Grand Rapids Michigan
    Even the tweeter might not be turned up very loud. There may just be a lot of energy in his signal that the bulb is absorbing. Either way he should rethink his signal chain a bit before he blows the tweeter. Depending on the cab and his tonal needs he may want to disconnect it for now.
  9. morgansterne

    morgansterne Geek U.S.A.

    Oct 25, 2011
    Cleveland Ohio
    these bulbs used to light up in my old band's peavey pr15 PA speakers. It was REALLY bright in a darkened bar.
  10. loudness


    Dec 28, 2012
    I assure you gents, I'm ungodly loud. I rattle the paintings on the walls down the hall from our lockout.

    I have no idea how to turn the tweeter down, but I'm glad it wasn't the electrical disaster waiting to happen that I thought it was. My guitar player can probably assist.

  11. tdub0199


    Mar 4, 2010
    Atlanta, Ga.
    sounds like your tweeter may not like the fuzz/distortion.... but yes, it's a small automotive light bulb being used as a fuse like others have stated....
  12. CL400Peavey

    CL400Peavey Supporting Member

    Nov 7, 2011
    Grand Rapids Michigan
    I would figure out what kind of cab you are using, and figure out a way to get a second one. Split up the power and you wont have to worry about that bulb as much.
  13. aproud1

    aproud1 Don't surround yourself with yourself. Supporting Member

    Aug 13, 2007
    Cincy, OH
    I guess your name is fitting then?
  14. Gearhead17

    Gearhead17 Supporting Member

    May 4, 2006
    Roselle, IL
    There should be an Attenuation Pad on the back of the cab - this is the tweeter level control. Turn this to the left - probably all the way since distortion sounds awful in the tweeter. Tweeters on Ampeg cabs typically operate in the 4khz through the 10khz range. Reduce this frequency band and you should be just fine.
  15. Told ya.
    Anyway OP, the Steel Leather pedal, being an expander and tuned to frequencies that your tweeters see, is hammering your tweeter very very hard.
    As Peavey said, turn it down or blow it. Most 4x10's have a dial on the back for this. If not, remove the light bulb from the fuseholder to disable the tweeter.
    Oh, please wear earplugs for God's sake.
  16. will33


    May 22, 2006
    Upon failing to destroy the entire world, the Mayans have taken up residency in your little corner of it.

    Yes, it's the protection bulb and it's doing it's job. That pedal is likely putting out a ton of highend that isn't getting counteracted by the other pedals being at the end of the chain.

    Follow the advice already given.

    What sort of bass player needs the guitarists assistance with a technical problem?:confused:

    :D:D :bag:
  17. hdracer


    Feb 15, 2009
    Elk River, MN.
    Would a GP even know what a tweeter is?
  18. will33


    May 22, 2006
    Let's hope not.:D
  19. No no no. They weren't actually going to do it themselves. They just gave us a date to shoot for.
    Then again, they didn't.
  20. will33


    May 22, 2006
    Apparently their drummer couldn't land on the one after his fill.