Gallien Krueger MBE 212 speaker problem

Discussion in 'Amps and Cabs [BG]' started by Carlo Vanoni, Dec 28, 2014.

  1. Carlo Vanoni

    Carlo Vanoni

    May 20, 2014
    Hi, everyone!

    I've had a GK MBE 212 for almost an year. I used it with an Aguilar TH500.
    Some days ago, I started hearing a huge "vibrating" noise when playing low notes (B->G). I made some tests to find the source of the problem, and I discovered it was the top speaker that outputs this noise.
    I removed the speaker to have a look. The cone looks ok, but I discovered a weird problem. The back of the speaker (the mechanical part that contains the magnet, I suppose) can move a little in the speaker support (in the "healty" speaker it is well anchored with the speaker basket). I suppose the noise is generated by this moving part. To better understand the problem, I've attached an image, with the "moving part" highlighted.

    Now, the real question.
    The cab is still inside the guarantee period, but it seems that GK warranty doesn't cover speaker problems. Better, it doesn't cover problems due to speaker misuse or simple decay.
    I don't think that this problem is caused by the mentioned reasons. It looks more like the speaker part detached from the speaker basket (faulty welding?), and in this case I think that this is more a factory problem.
    What do you think about it?

    Thanks a lot!

    Attached Files:

    • cono.jpg
      File size:
      48.4 KB
  2. JACink


    Mar 9, 2011
    I would try the guarantee first. It should cover any manufacturing defects. If they will not cover it under the guarantee, then at least they will tell you the issue and how much it will cost to repair.
  3. Carlo Vanoni

    Carlo Vanoni

    May 20, 2014
    Hi JACKink, thanks for the advice.
    I've asked here to hear some opinions first, since I have to wait till mid January to have info from GK technicians.
    Also, I have to ship the cab to the italian GK center, that costs me a little; if it turns out the problem is not due to manufacturing defects it cost me twice, and the cab had to travel for nothing.
  4. Rick James

    Rick James Inactive

    Feb 24, 2007
    New Jersey
    That donut shaped piece should be firmly glued to the back of the speaker. If its loose its a defect.
    B-string likes this.
  5. Carlo Vanoni

    Carlo Vanoni

    May 20, 2014
    Quite happy to hear the word "defect" this time :)
  6. You should not have to ship the whole cab, just the speaker. [email protected] may be able to help things along with your distributor when they return from holiday break. The speakers are manufactured by G-K not a third party so I would guess they will want to know of any bonding failure.
  7. Steve Dallman

    Steve Dallman Supporting Member

    Years...heck, decades ago, I bought some used 2X15 PA speakers. The store said they had just had the speakers reconed as they were breaking up.

    They still broke up. I came to find the bonding, as with your Gk, had failed on all the drivers. In one postition, they buzzed, but shifted to the other, they were fine.

    I used industrial epoxy we had at the plant and never had another problem. The store had reconed the speakers for nothing.
  8. Carlo Vanoni

    Carlo Vanoni

    May 20, 2014
    @B-string, thanks for the mail address. I will ask them (I will wait for mid-January anyway) befor sending to the italian distributor (haven't heard such good reviews about the italian distributor...). About sending just the cone, well, it scares me even more than sending the whole cab (haven't heard good reviews about italian shimpent companies, too...).
    @Steve Dallman, if I get it right (I'm not that good at english for techies), you had similar problems and solved the issue by welding the moving part of the speaker. Did I get it? Of course I will first ask for an under guarantee intervention. But I'm glad to know that I can repair it autonomously (well, sort of) and cheaply if such a thing will happen again in some years.
  9. JACink


    Mar 9, 2011
    Non è saldatura , è un tipo di colla molto forte chiamata epossidica.
  10. Carlo Vanoni

    Carlo Vanoni

    May 20, 2014
    TalkBass translator 1.0 :)
    Well, what about welding the mechanical parts instead of using epoxy? If done right, welded parts will remain "glued" together forever. Of course the mechanical parts must be made with the proper metal, otherwise they can't be soldered. Are there also some problems regarding the high temperatures used for welding?
  11. Carlo Vanoni

    Carlo Vanoni

    May 20, 2014
    After two months, I've finally managed to send the cab to the tech support and get it back repaired.
    It was repaired under the guarantee, and this is a good thing.
    The cone was not replaced, but it was repaired using some sort of glue, like SteveDallman said. And this is ... well ... I don't know if it is a good or bad thing.
    Haven't tested yet, so first thing to do is plug in the cab and play.
    Then, I hope the fix will prove to be reliable and durable.
  12. Carlo Vanoni

    Carlo Vanoni

    May 20, 2014
    Tested the cab. The sound seems ok (no more heavy distorsions), and the glue sirvived two hard rock set in our reharshal studio, so I suppose it will last long.
    Case dismissed.
    S-Bigbottom likes this.
  13. JACink


    Mar 9, 2011
    I'm glad it worked out.