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Thread: Noise in 2235H

  1. #1
    Senior Member Guido's Avatar
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    Noise in 2235H

    Today I got my K140 reconed as 2235H. I started to break them in and one work perfect.
    Unfortunately the other one makes some clicking noise. Its not loud and not really clicking. It's like fluttering with something touching the cone. Checked the wires, ok.
    It seems to come out of the dust cap inside the voice coil. When I'm moving the cone there is no sound or scratching.

    What the h... this could be?

    Thanks for help
    BLS Reference on Passlabs XA 30.5 + Everest DD66000 clone on Pass XA 100.5

  2. #2
    Moderator / Treasurer/Marketplace Czar boputnam's Avatar
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    I started to break them in - how? Were you bench testing them outside of the cabinets?

    It "sounds" like (sorry...) you might have a slight voice-coil rub from mis-alignment of the cone/spider assembly. "Fluttering" sounds like the sorrowful symptom.

    If you have a tone generator or that handy BassZone Test CD (http://basszone.stryke.com/) select something in the 30 - 50 Hz range, and ease the signal into the driver on a bench, listening closely. You should hear nothing...

    If you hear rubbing, you can try and very VERY gently apply asymmetric pressure moving around the cone and see if it worsens or disappears. If it disappears, I believe there is a problem in the voice coil positioning in the gap.

    Good luck!
    Last edited by boputnam; 06-30-2003 at 07:58 PM.
    bo

    "Indeed, not!!"

  3. #3
    Senior Member Guido's Avatar
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    noise in 2235H

    Hi Bo!

    Thanks for fast reply.

    I did test them outside the cabs.

    I will try to check the misalignment as you said tomorrow as it is 1AM here.

    If there is that problem, what can I do. Can it be adjusted or is the cone for the waste bin?
    BLS Reference on Passlabs XA 30.5 + Everest DD66000 clone on Pass XA 100.5

  4. #4
    Your Memory Lives On RIP Tom Loizeaux's Avatar
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    If there is a problem with the coil alignment, or any other re-cone problems, you should return the driver to the people who did you re-coning for a re-do!

    Tom
    Last edited by Tom Loizeaux; 06-30-2003 at 06:29 PM.

  5. #5
    Moderator / Treasurer/Marketplace Czar boputnam's Avatar
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    Tom's right, I'm 'fraid, Guido. The spider and surrounds need be redone - that is, re-centered, and that will take a new recone kit

    Bummer... Not so much the hassle, as the lost time! Ugh! You could possibly do the work yourself, if you can't find a good shop!
    bo

    "Indeed, not!!"

  6. #6
    Senior Member Guido's Avatar
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    Today I called the reconer.
    We agreed that I send the speaker back. this means another 2 weeks waiting

    I hope they will not make any problems because of the reconing from K140 to 2235H

    Thanks for your help guys!
    BLS Reference on Passlabs XA 30.5 + Everest DD66000 clone on Pass XA 100.5

  7. #7
    "new and improved" JBL Dog's Avatar
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    boputnam:

    Is it possible to salvage the cone and voice coil of Guido's 2235H kit if they have not been damaged? Just replace the spider, dustcap and surround? Ironically, I have a few 2235H's that have similar issues and my speaker guy (JBL authorized for over 20 years) says he can salvage the voice coil and cone if they are in good condition (both spiders are bad).

    Thanks!

    This message comes from JBL Dog

  8. #8
    Moderator / Treasurer/Marketplace Czar boputnam's Avatar
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    "salvage the voice coil and cone "


    JBL Dog...

    I've been thinking about your question off-and-on while travelling today, and you "could" salvage the cone and voice coil, but by taking the assembly apart you run the risk of increasing the chances of misalignment on reassembly - lots more pieces to align versus the JBL kits which are pre-assembled.

    Alternatively, you could soften the glues (using MEK) on the spider and surround, and merely try and reposition the wrongly installed kit - this may be what Guido's shop may try and do. I guess I'd try that if it was the last recone kit around, and you could feel comfortable you could "convince" the cone/coil into proper position, but you better be listening hard for any misalignment, and be gentle. And don't be rude to the surround...
    bo

    "Indeed, not!!"

  9. #9
    Senior Member GordonW's Avatar
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    JBLDog,

    I"ve actually done the operation you mention, a few times, with JBL and other speakers... cutting out the dustcap, removing the assembly, applying a new spider and surround, and shimming/re-assembling the speaker.

    It really depends on WHY the original installation of the kir was rubbing... if it was simply an original alignment flub, then yeah, this procedure will almost universally take care of problems. HOWEVER... if the voice coil was WARPED (which can be done, rough handling of the kit before assembly), then no amount of re-shimming and reassembly is gonna make it run clean.

    A good reconer/rebuilder should have a good enough eye, to tell whether a kit is reusable... it takes some experience and feel... but if it's done with non-defective and non-damaged parts, this kind of rebuild can work...

    Regards,
    Gordon.
    who just got thru doing this to a whole bunch of old EPI 8" woofers, due to having to re-glue loose magnets/pole pieces... got 'em ALL to work again!!

  10. #10
    Senior Member Guido's Avatar
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    Oh Oh!!
    I did send the speaker back and they checked their work. Now they say the “fluttering” is caused from demagnetised basket.
    Could this be the case???
    BLS Reference on Passlabs XA 30.5 + Everest DD66000 clone on Pass XA 100.5

  11. #11
    "new and improved" JBL Dog's Avatar
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    ferrite driver demagnetized??

    Is that possible? I would seek a second opinion.



    This message comes from JBL Dog

  12. #12
    Moderator / Treasurer/Marketplace Czar boputnam's Avatar
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    From "Click and Clack"

    I say, boooooo-gus !
    I agree with JBL Dog - that is nonsensical.

    Your description was perfect for a misalignment. Just MHO!!

    See if you can get a new JBL kit (maybe even through the shop giving this "advice") and do it yourself!
    bo

    "Indeed, not!!"

  13. #13
    Senior Member Guido's Avatar
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    Stooooop!!!!

    Hey Guys! I let them recone the 2235H cones in a K140 Basket.

    Alnico!
    BLS Reference on Passlabs XA 30.5 + Everest DD66000 clone on Pass XA 100.5

  14. #14
    Moderator / Treasurer/Marketplace Czar boputnam's Avatar
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    "I got my K140 reconed as 2235H"

    Yea, I got that part, but then you got noise that "sounds" like coil rubbing. I don't know what Alnico has to do with coil rubbing, if that's what it is.

    You have confused me, Guido... Help?
    bo

    "Indeed, not!!"

  15. #15
    Senior Member Guido's Avatar
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    Hello Bo!

    No it's not coil rubbing. As I wrote before it's more like "fluttering".

    Another interesting thing is when I close the vent on the backside of the magnet it's like breathing.
    I think the defect speaker moves more than the other. When I partially close the vent it breathes more than the other and it makes slightly "fluttering" sound.

    They say its demagnetized magnet. Could be possible as the baskets are bought used.
    BLS Reference on Passlabs XA 30.5 + Everest DD66000 clone on Pass XA 100.5

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