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Thread: JBL 4343 restoration, progress and quite possibly a lot of question along the way

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  1. #1
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    JBL 4343 restoration, progress and quite possibly a lot of question along the way

    I've had these speakers for approximately two years now and they've been in dire need of restoration. Have not come around to it as they sound so darn good, and I didn't have any good substitutes to use while I put in the work until now.

    I don't know everything about these speakers, but as far as I know these began their life in the JBL factory as the grey utility versions, they were then painted black with a blue baffle by Guido in Germany, but later left for Norway and was owned by Rolf. Rolf upgraded the speakers with what I think may be the charge coupled N3145 networks by 4313B on these forums. The networks were built by Guido. The crossover network does not have a passive section between the bass and mid, so they require active crossover. There was also an attempt to put American walnut veneer on the cabinets, but after some time the glue came loose and it has to be redone.

    The drivers in these are 2235h for the lows and 2121H for the mid. Other than that they're stock with 2420 on a 2307 horn, and the wonderful 2405 for uhf. The 2308 lenses are also original JBL.

    The idea is to restore the speakers into the beautiful walnut version. This is my first attempt at anything like this, so I'm sure there will be a lot of questions as the thread progresses. I also hope that people who see anything that doesn't seem right make some noise so I can correct it. I will spend a lot of time on this project as I want them to be in pristine condition when the job is done. These will be in my possession for the rest of my life and the thread can act as a fun resource for those who end up with them after me.

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    Pulled the veneer and getting ready to remove the crossover.

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    Closeup of one of the networks.

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    Removing the internal insulation and getting ready to remove the front trims and sand the whole thing down.
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    Removed the front trims using fein. Got most of it off after this image by using a sharp knife, but I will also have to recess the front a bit to fit the new walnut front trims as it's too far away from the baffle. If anyone has a 4343, please measure the distance from the lower baffle to the edge of the trim.

    Will use a flush trim bit to get it shorter before gluing the walnut in place, then do the veneer and lastly route the angle on the trim.

    It's a shame I can't remove the lower baffle, it seems to be glued in place. Would make a lot of the sanding work easier if I could remove it.

    ---

    Do I have to sand all the way down to the wood before putting on the veneer? The people who know veneering says the substrate must be completely level. Can I use a car filler type product to remove any dents or uneveness before veneering?

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    Sanding almost complete on one of the enclosures. This went faster than anticipated. Thank you Bosch!

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    Contemplating adding some light weight bracing to the mix. Any suggestions where I should add them?

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    Senior Member Ed Zeppeli's Avatar
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    Great project.....following.
    DIY Array, 2242 sub, 4408, 4208, Control 8SR, E120 Guitar cab, Control 1, LSR305.

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    Thanks Ed! Hopefully the result will be as great as the enthusiasm I got for this project

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    Some corners on the boxes have some ugly dents to them. Was thinking I could use my new fancy pants plunge saw to do a 90-degree cut or use the router to make a cut for an inlay which is glued in place to get sharp corners before veneering. What's common practice in these situations? Not a wood worker by a long shot

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    Senior Member macaroonie's Avatar
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    Router. Take as much as you need to remove the error. Make an inlay +1mm of the size of your rout then use a flush trim bit to clean it up.

    Simple

    Nice project

    Did you eventually score those PA boxes ?

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    4343B on Canuck Audio Mart.

    Hi there!
    I don't know how to post a new note so I'm using this one! Sorry!
    For anyone interested!
    Cheers!
    Christophe

    http://www.canuckaudiomart.com/detai...35bf9-70327121

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    Quote Originally Posted by Wagner View Post
    Not 100% but preferable to replacement non numbered foilcals.
    Give your originals a very HARD press between sheets of glass
    I mean HARD with wood blocks and "C" clamps
    Clean them thoroughly after pressing for a day or two and then shoot them with a light even coat of Testor's "Dull Coat"
    The patina will no longer be the final word on accuracy but all the little flaws and imperfections will blend together beautifully to the pint of being invisible; what you'll wind up with is a very presentable pair, perfectly flat and any little dinks and surface imperfections will be GONE
    I have done this myself and was very pleased with the results
    My pair was so bad this technique was a last resort before giving up and buying the reproductions
    Worked out fine
    Thanks, I thought nobody was reading as it was so quiet and my detailed posts and images of minute details are probably boring people to death, lol.

    That's very good advice, I will give the the process a try and clamp them between two sheets of glass or other hard materials. The dull coat is not readily available here, and will be imported together with something else to save on shipping.

    Could you do a mug shot of the present state of your foilcals if possible? Would be nice to see how the dull coat looks.

    Quote Originally Posted by Challenger604 View Post
    Hi there!
    I don't know how to post a new note so I'm using this one! Sorry!
    For anyone interested!
    Cheers!
    Christophe

    http://www.canuckaudiomart.com/detai...35bf9-70327121
    Oh, you, you cheeky bastard!!! Hahahaha, just flipping with you. They look good. Are they yours? If so, can you do me a favor and measure the front trim edge to baffle for me?

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    There are two measurements as you can see by the arrows. One where the massive walnut starts and all the way from the baffle to the walnut trim.

    You can post a new thread to the marketplace here if you'd like: http://www.audioheritage.org/vbulletin/newthread.php?do=newthread&f=5

    edit: Didn't realize it was you until later, Challenger604. So I guess they're not yours.

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    These baffles are making me thirsty

    The baffles are finally done. It has been quite a lot of routing, gluing, sanding and fixing. I've used car body filler to make things flush and will probably paint the rare side as it looks very ugly with all the inlays. Been using very good glue which expands and can't imagine any weak spots on these now.

    Have also plugged the hole for the midrange driver as I want to install terminals to make sure it's sealed.

    First one.

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  10. #10
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    Second 4343 baffle

    Baffle numbero dos.

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