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Video added: How do you know what's wrong with a driver

Discussion in 'Amps and Cabs [BG]' started by bassestkkm, Feb 20, 2016.


  1. I've got an old Acoustic 301 cab with a non original CV 187 in it at 4ohms. But the speaker has a rattle. It's like it's not all in one piece. But the cone moves and looks well except for the pushed in dust cap. During the 9V test the speaker extends fully in either direction but it sounds like static. This sound continues when it's properly wired up as well.

    Any ideas? Can it be fixed relitavely cheaply? Otherwise I've got a Carvin 18" loudspeaker that was in there when I got it. Sounds decent enough to me.
     
  2. Something - dirt or coil varnish - has gotten into the speaker coil gap. It sounds like static because the mechanical noise from the dirt rubbing in the gap between the speaker coil and the magnet goes right into the speaker cone.

    Can your driver be serviced for cleaning? I've serviced an old Peavey Black Widow speaker this way. The BWs have a piece of foam close to the coil gap that turns to goo over the years and gums up the gap. Cleaning costs you nothing.

    If the speaker coil is coming apart, you'll have to get that repaired. I don't know how much repairing or replacing the speaker coil would cost.
     
  3. When you give it the 9 VDC, is the static sound continuous or does it only occur for the moment the cone is moving?
     
  4. It's different from a properly working speaker. I've got the Carvin for comparison and that one goes once and then it's silent. Not so in the case of the CV. It's like there is a bad connection and it's being scraped along. So a continuous static.
     
  5. I'm not sure if it can be serviced. Is there a way I can check?
     
  6. google the speaker model/number to see what folks report as common failure modes and repair procedures. If the speaker magnet is bolted to the basket, then it can likely be removed.
     
  7. Debris in the voice coil's air gap would only make noise when the voice coil is moving. If you have continuous crackling with DC applied, that points to a loose electrical connection. Check them all, esp the terminal plate and tensile leads.
     
    agedhorse and BassmanPaul like this.
  8. I have a small 30 watt guitar speaker that I connected to the cab. Mind you it was still laying down. But when I turned it on it had the click of turning on and then it was silent. Then when I started playing through it it started making static noises also no with whatever I was playing. It was more a rattle but still similar. I cleaned the terminals before connecting the new wires and I think it may have helped. I'll try to post a video. It might make it all more clear.
     
  9. Just added a video for reference. I'm not too familiar with speakers but I think you may be right.
     
  10. Also could be a torn or loose spider.

    speaker.
     
  11. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    Sounds like some loosen wires of the VC, caused by to much of heat.
    Do you prefere dirty sounds from pedal board?
     
  12. mmbongo

    mmbongo Five Time World Champion Supporting Member

    Aug 5, 2009
    Carolinas
    Yeah that speaker is toast.
     
  13. Thanks for the picture. Perhaps I'll have to show someone who knows speakers a little better than myself. I would like to repair it though.

    I generally play with a clean sound. This speaker I bought from someone else so I do not know how well they treated it before me.

    I will send an email out to them and see what I get in response. Hopefully they can help me out as you folks have.
     
  14. Sounds toast to me. I don't know how badly it was abused in its past life. But it doesn't have rub which makes me hope that I can repair it. It's in an Acoustic 301 cab so I'm just trying for a bit closer to normal.
     
  15. Josh Thatguy

    Josh Thatguy ~¿~ Supporting Member

    That vc. = sign.
     
  16. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    sjrash likes this.
  17. Unfortunately they stopped doing speaker repairs. Unless I read their site wrong and they only stopped the record kits.
     

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