JBL L200 Studio Masters-Pics

Discussion in 'Speakers' started by GD70, Jul 29, 2018.

  1. GD70

    GD70 AK Subscriber Subscriber

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    No way they will be upstairs anywhere! My wife is the major obstical, all 120lbs of her!
     
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  2. Alobar

    Alobar Pulling out of the Last Chance Texaco.. Subscriber

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    It's called negotiation!
     
  3. GD70

    GD70 AK Subscriber Subscriber

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    Not with these! I can swap out other speakers the size of my AR3's but nothing larger! I have two systems on the main floor now, and getting the second one was negotiated quite a bit! She's great with this hobby, as long as it doesn't take over the house, it's all good.
     
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  4. GD70

    GD70 AK Subscriber Subscriber

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    So I've been really enjoying these. Big effortless un-distorted sound at any volume. Recently I was hearing some cabinet vibrations from one cab.
    So I pulled the woofer and while inspecting the interior, pushing & pulling for any signs of something loose, I discovered the cross brace the tweeter bracket screws to was loose from the cabinet. The original glue had let go. Just a tiny bit of movement.
    So I went in and epoxied it along the bottom where it was glued to the back panel of the cab.
    So cool to be the first to open this up since it was built. Here's a look inside. I'll report back once it's back together.
    Glenn
    IMG_7957.jpg IMG_7958.jpg IMG_7965.jpg IMG_7960.jpg IMG_7952.jpg IMG_7956.jpg
     
    Last edited: Feb 10, 2019
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  5. Alobar

    Alobar Pulling out of the Last Chance Texaco.. Subscriber

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    Someday when you are in there poking around, crack open one of those compression drivers and see what the foam looks like on the back cap. After all these years likely it will be just starting to disintegrate or worse' has completely broken down.. I think there are factory replacements around, I made my own.. good till the next owner gets em after I have said my goodbyes at the pearly gate..
     
  6. GD70

    GD70 AK Subscriber Subscriber

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    Yeah, I've been thinking about that. Once the foam hits the crapper, how is the sound effected?
     

     

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  7. Alobar

    Alobar Pulling out of the Last Chance Texaco.. Subscriber

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    Well that's a question I probably couldn't answer but when that foam does go it gets very sticky and will stick on that diaphragm for one. Possible ringing off the back cap from nothing left to deaden it could also be heard I suspect. I didn't notice that much sq improvement after doing mine, but those had just started their decline and only a little bit had crumbled and stuck on to the diaphragms.
     
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  8. GD70

    GD70 AK Subscriber Subscriber

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    Yeah, I should bite the bullet and just do it.
     
  9. Alobar

    Alobar Pulling out of the Last Chance Texaco.. Subscriber

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    Yeah it's pretty easy. . If you have ever pulled a transmission out of a 70's era car you'll have no problem! :biggrin:
     
  10. Freddymac2

    Freddymac2 Super Member

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    Come on Alobar, it can't be that bad???
     
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  11. GD70

    GD70 AK Subscriber Subscriber

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    I’ve done that several times. Ok, I’ll keep going.
     
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  12. Alobar

    Alobar Pulling out of the Last Chance Texaco.. Subscriber

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    Yeah all kidding aside it will be super easy to pop the 4 screws on the cap and take a quick look for crumbling. If it is intact, just put the cap back on and forget about it,you probably have years. The foam will likely be in pretty fragile shape so don't push on it with your fingers if you intend to keep it in there. . If you do take it out you will want to pull the leads to the diaphragm at which point you should get yourself a bronze #2 Phillips and be very careful to hang onto those steel screws! That magnet is very powerful and those diaphragms delicate.l
     
  13. Alobar

    Alobar Pulling out of the Last Chance Texaco.. Subscriber

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    Actually, after looking at the pictures I taken when I pulled my LE85's apart it looks like it could possibly have been safer for me to pull the other end of the jumpers that go to the binding posts instead of how I did it in order to replace the foam. But even so you still should take that diaphragm off (3 screws) while it's opened up as it will be just too vulnerable sitting on that huge magnet to any small bits of metal getting close. Cannot stress enough to keep the work area completely clear of any ferrous bits... Take care in there!
     

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  14. toddalin

    toddalin Super Member

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    If the foams look good, and you want to keep them, don't even touch them. At this age, they will literally disintegrate at your touch. Mine were doing this over 10 years ago, so...

    When I replaced mine, I used the carpet padding that looks like different colored "head cheese." I just cut a circle, cleaned out the old foam, and used some spray adhesive on the padding to attach it.

    Is this the best choice of materials??? :dunno: But seems to do it's job.
     
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  15. GD70

    GD70 AK Subscriber Subscriber

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    Yeah, I'll definitely unscrew the leads to the cap. Good tip!
     
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  16. toddalin

    toddalin Super Member

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    While they are silver in color, the horseshoe clips are ferrous! As soon as you loosen those screws and remove the horseshoe clip, it will instantly be attracted to the magnet via the dome of the diaphragm and will leave marks on the diaphragm! (They often look like vampire bites.) You must be mindfull and have the wires well in hand when loosening those screws and keep the clips away from the diaphragm.

    Also, if at all possible, do not use a ferrous screwdriver. Again, just looking for trouble.
     
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  17. GD70

    GD70 AK Subscriber Subscriber

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    Thanks for this info! I think I would only remove them from the cap as that's what needs cleaning and new foam glued to.
     
  18. Alobar

    Alobar Pulling out of the Last Chance Texaco.. Subscriber

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    Just tape those leads off all the same, use non ferrous screwdriver, and get the screws out of the area...You'll be fine..
     
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  19. GD70

    GD70 AK Subscriber Subscriber

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    Thanks!
     
  20. toddalin

    toddalin Super Member

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    Here's one on a 4435 with the dreaded vampire bites I was alluding too.

    [​IMG]
     
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