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Thread: Jbl 4348

  1. #1
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    Jbl 4348

    Can someone help me help me
    I am lookin for JBL 4348 lowfreq crossover network.



    Regards
    Ari Oskarsson

  2. #2
    Administrator Robh3606's Avatar
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    "I could be arguing in my spare time"

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    Quote Originally Posted by Robh3606 View Post

    Thanks for the information

    I think at both coils are air coils 2.8 mh and 8.2 mh
    the problem is I need someone to make the coils for my accurately the same like the orginal
    I need pair of both



    regards
    Ari

  4. #4
    Administrator Robh3606's Avatar
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    I think at both coils are air coils 2.8 mh and 8.2 mh
    No they are not. Take a look at the Tech Sheet. They are definately cored. Take a look at the ERSE coils they have very low DCR for there values and are readilly available.

    Rob

    http://manuals.harman.com/JBL/HOM/Te.../4348%20ts.pdf
    "I could be arguing in my spare time"

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    Quote Originally Posted by Robh3606 View Post
    No they are not. Take a look at the Tech Sheet. They are definately cored. Take a look at the ERSE coils they have very low DCR for there values and are readilly available.

    Rob

    http://manuals.harman.com/JBL/HOM/Te.../4348%20ts.pdf

    I find a pictures of the 4348 low network and I dont se any metal in the center of the both coil, they are not C-coil?



    Regards
    Ari

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    Take a look at the ERSE coils they have very low DCR for there values and are readilly available.

    Rob


    I look on the ERSE homepage and ask them about the coils I need for the crossover, but they have not answer me.



    Regards
    Ari

  7. #7
    Senior Member grumpy's Avatar
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    Name:  4348_2_ph.jpg
Views: 4826
Size:  15.8 KB

    Schematic shows iron/laminate core, but the picture at the Japanese/Harman site
    sure looks like air core

    Wouldn't be the first time that a prototype photo -or- a schematic error
    made it into publication... or a production change didn't match an old picture... or ...

    I'd -think- a lower-loss inductor would make sense here, but I'm not about
    to criticize whatever the designer intended. Might have to ask someone to pop
    open their 4348 for you...

  8. #8
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    Quote Originally Posted by grumpy View Post
    Name:  4348_2_ph.jpg
Views: 4826
Size:  15.8 KB

    Schematic shows iron/laminate core, but the picture at the Japanese/Harman site
    sure looks like air core

    Wouldn't be the first time that a prototype photo -or- a schematic error
    made it into publication... or a production change didn't match an old picture... or ...

    I'd -think- a lower-loss inductor would make sense here, but I'm not about
    to criticize whatever the designer intended. Might have to ask someone to pop
    open their 4348 for you...

    I have find more pictures of the 4348 low crossover network and both coil looks like air core.


    regards
    Ari

  9. #9
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    Not all the PCB are shown.

    There are 10 chokes and I dont see that many in the image.

    Typcially JBL allows for a total dcr of around 0.6 ohms in the woofer low pass sections. So select you components accordingly.

  10. #10
    Senior Member grumpy's Avatar
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    Look harder... they're there.
    It would be easier if a microscope weren't needed with that image

    Matches the assembly numbers 12, 13 on the tech sheet pdf as well
    (one HF assy, one LF assy)

  11. #11
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    I guess I need new glasses or they are tiny chokes....LOL

  12. #12
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    JBL 4348 crossover

    I send email to Harman Audio in Japan and ask them about the coils in the lower crossover network, they told me at the both coils 2.8mh and 8.2mh are air core coils





    regards
    Ari

  13. #13
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    I really does not matter if the coil is designed correctly.

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