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

  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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    Quote Originally Posted by macaroonie View Post
    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 ?
    Thanks (again!). That's a very good plan. Will be painful to route in them, but no turning back now.

    I've tried to reach the seller on multiple occasions but no replies, so I guess they're long gone I'm using 2404 [>10khz] + (2360A w/2446 [800-10khz]) + 2 x 2226 [40-200/800] per side now, active xo w/miniDSP 4x10 HD. It rocks, and I haven't even optimized it yet. The dynamics are off the chart!

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    My Gawd, these restoration pictures from another chap made me excited!!!! GORGEOUS!!!

    http://www.audioheritage.org/vbullet...atest-project-!

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    These cabinets must be routed a bit because the front "lip" extends too much. But by how much?

    Can't find plans for 4343 on the site.

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    I like the meow factor you are adding!

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    4343 cabinet, some info
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    43XX (2235-2123-2450-2405-CC 3155)5235-4412-4406-4401-L250-18Ti-L40-S109 Aquarius lV-C38 (030) 305P MkII

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    Quote Originally Posted by Chas View Post
    I like the meow factor you are adding!
    Good eye there!

    Quote Originally Posted by Odd View Post
    4343 cabinet, some info
    Thank you very much, Odd. Appreciate all the help you've given me!

    I know there are some baffle plans on here too, but can't find them even though I've been searching like crazy. The PDF file you attached doesn't have the dimensions I'm after unfortunately.

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    One of the enclosures were not perfectly rectangular. There was about 1mm too much around the middle of the enclosure on one of the sides. Quite possibly a mistake by JBL QC back in the days as there is no indication that it's a result of something else. It was the center bracing and baffle which was a little off, so I used Fein to correct for it. Will make it look pretty by using car body filler and expanding glue. The prior front trims were build around the 1mm bump and it had to be corrected to make a seamless integration between the veneer and the trim because 1mm off at the center made it look much worse on each corner.

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    The 4343 restoration continues

    The restoration is moving forward, albeit a bit slow. As I've said, I want these to be pristine and there are small blemishes which are time consuming to fix here and there. I was thinking about making new upper baffles, but are going to do my best to restore the originals.

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    Got the foilcals off using a heat gun, patience, spackle knife and a women's touch. They've been off before and unfortunately the job was not as gentle as mine, so they are probably due for replacement. Kind of sad, as replacements are expensive and lack the serial numbers... Got to think hard about what to do. They will be cleaned up and hidden in a plastic pocket inside the cabinets behind damping if they're replaced.

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    This tear out needs to be fixed, and I had to remove the original gaskets on the baffle to get to it.

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    I is the jiggermeister

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    Cut

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    It fits! Have glued it with expanding glue and will flush trim the thing later.

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    Turned out all right.

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    The baffle was screwed in with some wood screws on one speaker, so I drilled the holes bigger

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    and are gluing in wood pegs. Ran out of wood pegs, so need to get more tomorrow. When it's all done I will use car body filler and sand to make everything even.

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