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Loud Buzz/Hum in my Cab.

Discussion in 'Amps and Cabs [BG]' started by Erad, Aug 2, 2012.

  1. Erad


    Aug 2, 2012
    Hey everyone. I've been searching for answers all over. Nothing that I can find has really matched my issue.

    I have a GK 700RB head and a 410rbh cab. I've had it for a few years, it hasn't been played much other than a few shows and practice at home.

    I've been playing it a lot in the past couple weeks without issue. But yesterday a mysterious buzz showed up when I turned it on. The buzz is very loud and you can hear it over playing.

    troubleshooting I've done:
    1. Still does it without a bass or cable plugged in.
    2. Volume does nothing to it, and neither does mute.
    3. The only knobs that lower the volume of the buzz is the Woofer knob (the boost knob lowers the strength of the buzz, but never gets rid of it completely.)
    4. if I press the "woofer hi cut" button in, it creates an extremely loud squeal. Ear piercing.
    5. there is also a much higher pitch buzz that is not nearly as noticeable until Woofer is turned all the way down (thus removing the low buzz) This higher pitch buzz is affected by the tweeter knob.
    6. Tweeter High cut button doesn't seem to change much with the high pitch buzz.

    Again, I haven't been playing it hard or anything. it stays in the same spot, no travel.
    The only thing I can think of that happened before that buzz showed up was a small power flicker. earlier that day. and I leave it plugged in 24/7 (always turned off though.)

    Any ideas what this could be? cost to fix? Any DIY remedies? Issue with head or cab?

    Thanks for all the information to come!
  2. Numbers 2 & 4 suggest the amp has something gone wrong in the preamp. You could troubleshoot that by plugging another preamp into the effects return, takes out the amp's own preamp. Even an active bass.

    Parts and labour to troubleshoot, not a whole lot of money for parts. Time to find someone who knows their way around the amp. Maybe an hour maybe two at the outside is my guess.
  3. dhomer

    dhomer Commercial User

    Apr 9, 2009
    Hickory Corners, MI
    Owner, Gigmaster Soundworks, Auth. greenboy designs builder, MI
    Try the head with a different cab. You may have a bad speaker.

    I had a new Eminence 3015 make a high pitched squeal running no more than a 30Hz sinewave.. Traded it in on warranty, problem solved..
  4. dincz


    Sep 25, 2010
    Czech Republic
    He's getting the noise with nothing plugged into the amp. Speakers don't generate hum.

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