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What to Look for in a Potentially Blown Driver?

Discussion in 'Amps [BG]' started by Count Bassie, Mar 13, 2014.


  1. Count Bassie

    Count Bassie

    Joined:
    Jun 10, 2006
    Location:
    Smithfield, RI
    I have a Bag End S-15D, one of a pair, and when I get to anything near performance volume the driver begins to sound crackly, raspy and distorting. It passes the 'push test' though. Is it possible that there's no evidence of being blown until it reaches a certain level of activity within the gap? Is this typical?

    I'm not going to like this...
     
  2. Count Bassie

    Count Bassie

    Joined:
    Jun 10, 2006
    Location:
    Smithfield, RI
    I've changed the battery in my bass, and tried it with 2 heads. No-brainer, right?...
     
  3. fdeck

    fdeck Supporting Member

    Joined:
    Mar 20, 2004
    Location:
    Madison WI
    Disclosures:
    HPF Technology: Protecting the Pocket since 2007
    Loose connection in the speaker wiring is a possible culprit.
     
  4. Count Bassie

    Count Bassie

    Joined:
    Jun 10, 2006
    Location:
    Smithfield, RI
    SM 400 driving the pair in bridged mode, playing reggae. BUT I was watching my lows, and took care to not hit them hard with the sub-sonic thing. Used a dose of low-mids, AE well below 12:00, Bass knob cut back just below 12:00...
     
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  6. Count Bassie

    Count Bassie

    Joined:
    Jun 10, 2006
    Location:
    Smithfield, RI
    I will look there. Thanks!
     
  7. Oren Hudson

    Oren Hudson

    Joined:
    Dec 25, 2007
    Location:
    Gastonia, NC
    Based on when it happens, you could have debris in the gap or the magnet shifted or both, assuming the dust cover and speaker surround are intact. One other problem I've had that sounds somewhat like yours is where the speaker lead wires connect from it to the frame. At higher volume, the cone was flexing so much that it was contacting the leads and making a very noticeable distortion type noise. As stated, check all connections from the speaker to cab to guitar. Even one of those can cause problems. Good luck. :)
     
  8. Count Bassie

    Count Bassie

    Joined:
    Jun 10, 2006
    Location:
    Smithfield, RI
    I'll check all this out. Many thanks you guys. :cool:
     
  9. Bassmec

    Bassmec

    Joined:
    May 9, 2008
    Location:
    Ipswich UK
    Disclosures:
    Proprietor Springvale Studios
    After you have finished checking the connections, I would also look very hard at the cone to make sure it has not picked up any radial crease in the cone either at the front suspension or at the spider as sometimes, on a push test the voice coil misses the magnet but
    when driven compresses the creases and causes the voice coil to bend to one side and drag on the magnet pole at higher power.:bassist:
    [​IMG]
     
  10. Count Bassie

    Count Bassie

    Joined:
    Jun 10, 2006
    Location:
    Smithfield, RI
    That makes sense, I get it. I'm at it just now, so I'll be back. Thanks!
     
  11. Count Bassie

    Count Bassie

    Joined:
    Jun 10, 2006
    Location:
    Smithfield, RI
    Ok. I opened up the cab, lifted the speaker. Re-attached the wires to the terminals, looked over the solders at the input jacks. Took a flashlight and looked for a crease at the spider, nothing. Put it back together, fired 'er up... :bag:

    One little moment of noise after a bit, after turning it up some. Then it was gone, and did not return! :hyper: Don't know, maybe it was some bit of oxidation from having been in storage, maybe I blew something out the vent. But all is well now.

    The SM-400 takes a little eq tweaking, but now I could finally pay attention! I turned it up to about 1/2-way on the Master vol- and the drivers did their Bag End thing. :bassist:

    So I think she's fixed- the Bag Ends are BACK!! Thanks everybody! :cool:
     
  12. JimmyM

    JimmyM Supporting Member

    Joined:
    Apr 11, 2005
    Location:
    Apopka, FL
    Disclosures:
    Endorsing: Ampeg Amps
    Always nice when a repair happens without any moneyshed.
     
  13. Matthew_84

    Matthew_84

    Joined:
    Nov 7, 2010
    Location:
    Toronto, ON, Canada
    Yeah, I've had to go through endeavours like that many a time. Sometimes it's a wire that started hitting the backside of the cone when it starts exerting at a certain volume. In many times it's just a loose screw in the cab somewhere rattling away.
     
  14. Count Bassie

    Count Bassie

    Joined:
    Jun 10, 2006
    Location:
    Smithfield, RI
    Yes indeed, Jimmy. Yes indeed.
     
  15. Count Bassie

    Count Bassie

    Joined:
    Jun 10, 2006
    Location:
    Smithfield, RI
    That kind of thing drives me quietly to distraction. Finding you can remedy it (maybe just by playing!) is like waking up on Saturday morning for school... :p
     
  16. Oren Hudson

    Oren Hudson

    Joined:
    Dec 25, 2007
    Location:
    Gastonia, NC
    Sounds like debris in the gap that, between you moving it and playing it, worked itself out. I've had the same experience. As Jimmy said, cheap fixes are far out. ;)
     
  17. Count Bassie

    Count Bassie

    Joined:
    Jun 10, 2006
    Location:
    Smithfield, RI
    Yeah, it's a great thing, sometimes, to just not panic and turn the thing over a few times. In your head, I mean! :D

    I was so enthused I went and re-jigged my speaker cables to all-banana plugs. :) Should've been done anyway, but now I felt like it...
     

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