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Thread: Delrin Replacement Sleeve Throats for 2" Compression Drivers 375, 2482, 2440, 2441

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    Member JBLPRO's Avatar
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    Delrin Replacement Sleeve Throats for 2" Compression Drivers 375, 2482, 2440, 2441

    Hello All....
    I am super excited to share some vintage JBL info with you. I spent some time with an engineer friend of mine and we came up with a 99 % perfect affordable replacement horn throat sleeve( JBL part #21251) for the 2” vintage compression driver family. The models that use this part include- 375, 2482 and 2440/2441. JBL discontinued these many years ago. They are manufactured from black Delrin ® and are NOT 3 D printed! They are SUPER strong and are VERY high quality! Precisely manufactured to replace the original JBL factory part.
    As many of you are already aware the original old aging JBL throat sleeves(most were bakelite material) have become brittle and crack easily when the drivers are packaged/shipped improperly. On top of that many of these drivers have lost their spec’d gauss making the magnet more prone to movement with impact thus intern cracking the aging brittle factory original throats. I see it all the time when these drivers are shipped! Compression driver value also decreases significantly with damaged throats. There is now a solution to have them repaired with a new sleeve. This is not really a DIY replacement as to do the repair properly the drivers need to be demagnetized/magnetized. I seen it done as a DIY but its not recommend as the unit will loose some charge when opened. There are other techniques of removing the throat without the need to open the driver but I do not have experience with this method.
    It's interesting that when JBL shipped these heavy 2” compression drivers way back in the 70’s and 80’s there was not much of an issue with magnet shifting. The original packaging was conservative not very big and, utilized a styrofoam partial clam shell. They were freshly charged tested, in spec and all was good to go!

    Please let me know if anyone is interested in seeing samples or pics.

    mk

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    Member JBLPRO's Avatar
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    Added a photo of the 2441 compression driver throat sleeve

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    Member JBLPRO's Avatar
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    Samples available

    If anyone is interested I will be more then happy to send out a few samples to anyone who is interested. I would love to get feedback. They have been tested and are a option as a replacement to the factory part.
    I am also puzzled why no one has responded to this post. I thought there would be more interest. Perhaps I missed the boat.... Seems like there was a lot more interest discussion years ago. Is this a sign I am getting old? Ive been involved/obsessed with JBL since 1974!

    PM me if your interested.

    mk

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    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by JBLPRO View Post
    I am also puzzled why no one has responded to this post. I thought there would be more interest. Perhaps I missed the boat.... Seems like there was a lot more interest discussion years ago. Is this a sign I am getting old? Ive been involved/obsessed with JBL since 1974!
    We are all getting old.

    First, how many folks are still running the old 2" exit drivers? A fair number I imagine, but less and less all the time.
    Second, how many of that group have cracked bakelite throats?
    Third, of those with cracked throats, how many realize it?

    Then, how many of the remaining folks are ready to demag and remag their drivers and perform a complete overhaul?

    Lastly, of those that check all of the above boxes, how many are regulars on this ever shrinking forum? A pretty small group, I imagine.


    FWIW: I applaud your taking this on. Spread the word, it would be shame to let these otherwise great drivers go to waste.


    Widget

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    Member JBLPRO's Avatar
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    Thanks for responding Widget. Makes me feel better that you made a comment. You are correct about the shrinking numbers of folks willing to do what I do with vintage JBL. When I do my clone builds and need to find the drivers for the boxes I am still amazed at the prices that these classic drivers demand. Especially good, not abused, clean working examples.
    I have four 2441's that need to be overhauled(cracked throat sleeves) to due poor packaging. And as far as I know only 2 shops are left in the US that have the required equipment to do a PROPER overhaul/restoration which REQUIRES the demag/remag procedure.
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