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Re-foaming the speaker of a GK 200MB

Discussion in 'Amps, Mics & Pickups [DB]' started by mormoyboy, Apr 19, 2015.


  1. mormoyboy

    mormoyboy

    Oct 9, 2012
    NWOhio
    I have a wonderful sounding GK 200MB combo amp (the all metal cabinet with the 12" is one of the best sounding amps for upright IMHO...) that had its speaker surround foam desintegrate.
    Does anyone have experience with refoaming one of these?

    Looks like PartsExpress makes a 12" defoaming kit that could work...?
     
  2. drurb

    drurb Oracle, Ancient Order of Rass Hattur; Mem. #1, EPC

    Apr 17, 2004
    Are you sure the surround is foam as opposed to rubber? It's important to maintain the correct compliance of the suspension. See here, for example.
     
  3. mormoyboy

    mormoyboy

    Oct 9, 2012
    NWOhio
    I'll have to call GK to find out - put in an email to them... given the disintegrated pieces in the amp, I thought it's foam - but I am not sure. thanks for the hint!
     
  4. Pilgrim

    Pilgrim Supporting Member

    I've replaced foam in a number of stereo speakers - quite easy. If you have a rubberized surround, I'd think the same principles would apply...but it may mean a re-cone due to the travel of a musical bass speaker.
     
  5. mormoyboy

    mormoyboy

    Oct 9, 2012
    NWOhio
    I think (I hope) it does not need not a recone job... was working fine until a few weeks ago - so the surround disintegration is somewhat decent and I didn't use it damaged at all... so once I figure out if its a re-foam vs. a re-rubber job for the surround, I hope to have a working amp again...
     
  6. robgrow

    robgrow Supporting Member

    May 1, 2004
    Cincinnati, Ohio
    Another common problem with the GK 200MB... The foam surround on the speaker (made by Pyle) deteriorates with time (all 200MB are 20+ years old).

    There have been reports here of people successfully replacing the foam surround on their speaker with a generic kit. Also factory-new replacement drivers (for the newer MB150) are available directly from GK (which I would recommend over most recone jobs).

    While either of these is a viable option, both involve taking the 200MB's cabinet apart to access the speaker. Successfully reassembling the cabinet after repairing/replacing the speaker can be difficult. The sealant/gasket material between the aluminum panels needs to be renewed or air leaks will result. Also the threads in the aluminum panels for the screws that hold the cabinet together are easily stripped. Good luck! (Been there, done that multiple times, and I'm in no hurry to do it again.)
     
    Last edited: Apr 19, 2015
  7. Brent Nussey

    Brent Nussey

    Jun 27, 2001
    Tokyo, Japan
    I did this to mine thanks to the kind advice of Francis Deck (member FDeck). Thread here: Gallien-Krueger 200mb speaker replacement | Page 2 | TalkBass.com I bought the refoaming kit from Newfoam in Rochester NY (Speakerparts.com), and it worked perfectly. They sent me a package with 2 rimgs/caps, and I just followed the instructions, I still have the second foam set. Amp sounds great.
     
    mormoyboy likes this.
  8. mormoyboy

    mormoyboy

    Oct 9, 2012
    NWOhio
    Thank You Brent!
     
  9. drurb

    drurb Oracle, Ancient Order of Rass Hattur; Mem. #1, EPC

    Apr 17, 2004
    Brent-- that's great information. Was the kit foam or rubber?
     
  10. jthisdell

    jthisdell Supporting Member

    Jun 12, 2014
    Roanoke, VA
    I did a pair of stereo speakers a few years back, actually pretty easy with the right foam kit. Good luck!
     
    mormoyboy likes this.

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