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Thread: JBL 4343 restoration questions

  1. #1
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    JBL 4343 restoration questions

    Hello!

    After having played with Guido and Rolf's old 4343B during the weekend I've decided to take the plunge and restore them both aesthetically and functionally, as I will keep these wonderful speakers for years and years to come. As I have never restored something like this, I'm sure there will be lots of questions I hope to get help with.

    These were originally grey and black, but Guido or an even earlier owner painted or sprayed them black. Rolf painted the baffle blue and sent them to a professional for a veneer job. Unfortunately the workmanship is poor, and the veneer is coming off at several places, especially the corners, maybe because the veneer has been glued directly onto the glossy black and earlier finish.

    I'll most likely only do the ground work, ie taking off the veneer, sanding both baffle and cabinet and send them off to a professional to do the veneer job. To save on costs I'd like to paint or do the baffle in blue myself.

    The dust covers does not seem original, as they have no badge that says these are 4343's, so I'll probably build new ones or buy a pair if they ever show up on ebay. This will not be first priority, as I think they look awesome without the covers.

    Also, the knobs on both l-pads has some dead spots and they make the associated speaker noisy when turned, so they may need to be replaced. Talked to a fellow Norwegian guy about this, and he suggested trying some contact spray and turning them a bit to see if the dead spots and sparkling sounds that came when turning them went away.

    Furthermore, when I removed the 15" to see the crossover, I noticed that one of the screws was not screwed in properly, as the nut that was supposed to sit at the back of the baffle was gone. It looked like something was put into the hole to hold the screw, but it came out very easily and should be fixed.

    Basically, my first questions are:

    1. Is the original finish American valnut, and are there any suppliers of this I can contact that you guys know of?
    2. The original blue color; does anyone have a color code or similar so they can mix the color in a regular paint shop?
    3. Is regular paint the way to go to get the baffle blue?
    4. If nobody has a paint code or similar, is it possible to buy the original blue color somewhere?
    5. Where can I get nuts that dig into the back of the baffle, what are they called in English and what dimensions are the screws so I order the correct one (as I have the original screw).

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    6. If using contact spray on the pots doesn't work out, what can I buy that is an appropriate and as close to original replacement as possible?

    Hope you can help me with some knowledge during this process, as I will not be able to do it without you.

  2. #2
    Senior Member 4343's Avatar
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    Cool

    Quote Originally Posted by DingDing View Post
    Hello!
    ...
    5. Where can I get nuts that dig into the back of the baffle, what are they called in English and what dimensions are the screws so I order the correct one (as I have the original screw).

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    6. If using contact spray on the pots doesn't work out, what can I buy that is an appropriate and as close to original replacement as possible?

    Hope you can help me with some knowledge during this process, as I will not be able to do it without you.
    That is called a "Tee Nut" or "T Nut" and it appears to be a 1/4-20 thread. (One quarter inch diameter with 20 threads-per-inch (TPI) pitch.) The other common size would be "10-32" thread, #10 screw, 32 TPI. A #10 is 3/16" or very close to 5mm. Don't try to use a metric fastener though, it will bind after seeming to go in OK for a while, BTDT.

    As for the L-Pads, I think these are very close to the originals, although the shaft length may be different, they sell short or long shafts so get the ones that match what you have.

    https://www.parts-express.com/speake...8-ohm--260-250

    I like to use a little beefier part, so would get the 50W version in the short version:

    https://www.parts-express.com/speake...8-ohm--260-252

    For all of them start here:

    https://www.parts-express.com/Search...itesearch=true

    DeOxit fader lube spray has almost always brought scratchy L-Pads back to proper operation for me, be sure to get the lube version so the corrosion does not come back...
    Mike Scott in SJ, CA
    Drive 'em to the Xmax!

  3. #3
    Senior Member Odd's Avatar
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    T Nut. Is "islagsmutter" in Norwegian. Can be purchased at some hardware stores. Maybe they have only metric. Switch to new Allen (Unbrako) screws.
    JBL blue, see here.

    Use Google to search the Lansing Heritage forum

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    Senior Member christo's Avatar
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    I suggest you read this thread as it covers the wood working/veneering part of your restoration. The hardest part of the veering process is the removal of the original veneer.

    http://www.audioheritage.org/vbullet...In-My-JBL-Shop

    If you decide to do the veneering yourself the best advice I can give is donít use a contact cement type glue it is a PIA as positioning the veneer of the surface is a one shot deal. Using a glue like Titebond II - Cross-linking polyvinyl acetate is an absolute pleasure as position the veneer is easy. I have used most of the techniques in this thread, they easy to implement and they work.

    Here is a site you can browse for veneer and then source closer to home www.oakwoodveneer.com

  5. #5
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    Thanks to all of you who have replied so far.

    Quote Originally Posted by 4343 View Post
    That is called a "Tee Nut" or "T Nut" and it appears to be a 1/4-20 thread. (One quarter inch diameter with 20 threads-per-inch (TPI) pitch.) The other common size would be "10-32" thread, #10 screw, 32 TPI. A #10 is 3/16" or very close to 5mm. Don't try to use a metric fastener though, it will bind after seeming to go in OK for a while, BTDT.
    I believe you're correct about 1/4-20 when measuring the screw and counting threads over 1". I'll let you guys know the dimensions when I've tried.

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    As for the L-Pads, I think these are very close to the originals, although the shaft length may be different, they sell short or long shafts so get the ones that match what you have.

    https://www.parts-express.com/speake...8-ohm--260-250

    I like to use a little beefier part, so would get the 50W version in the short version:

    https://www.parts-express.com/speake...8-ohm--260-252

    For all of them start here:

    https://www.parts-express.com/Search...itesearch=true

    DeOxit fader lube spray has almost always brought scratchy L-Pads back to proper operation for me, be sure to get the lube version so the corrosion does not come back...
    Great! I'll try DeOxit fader lube spray first. It doesn't seem like there are any Norwegian suppliers but I'll get the product on ebay. Looks like this is the one you're talking about.

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    Quote Originally Posted by Odd View Post
    T Nut. Is "islagsmutter" in Norwegian. Can be purchased at some hardware stores. Maybe they have only metric. Switch to new Allen (Unbrako) screws.
    JBL blue, see here.

    Use Google to search the Lansing Heritage forum
    Hi,

    I visited all the local hardware and furniture stores but nobody had them. Going to buy them from ebay as they are dirt cheap.

    Great thread on the JBL blue! Read through the entire thread and (posting here for later reference) it seems like RAL 5001, which is a European color std. is very close to the original, so going with that.

    Thank you for the tip! Will do that.

    Quote Originally Posted by christo View Post
    I suggest you read this thread as it covers the wood working/veneering part of your restoration. The hardest part of the veering process is the removal of the original veneer.

    http://www.audioheritage.org/vbullet...In-My-JBL-Shop

    If you decide to do the veneering yourself the best advice I can give is donít use a contact cement type glue it is a PIA as positioning the veneer of the surface is a one shot deal. Using a glue like Titebond II - Cross-linking polyvinyl acetate is an absolute pleasure as position the veneer is easy. I have used most of the techniques in this thread, they easy to implement and they work.

    Here is a site you can browse for veneer and then source closer to home www.oakwoodveneer.com
    Wow, that was an extremely helpful thread, and wow that guy knows what he is doing. I might try to do it as it's a great skill to have, but if all fails miserably I'll let the professionals do it.

    Great supplier of veneer, thanks. They ship worldwide, so probably going with them as it's hard to source here according to Norwegian DIY'ers.

    Fantastic, now I only need to do some shopping, wait for the materials and let the project start.

    I'll post pics as the project develops. I have to warn you all about the risk of foul language though, haha.

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    JBL 4343 Grill bolts(?) and plates

    Hi, got a few more questions.


    1. Does anyone have a file with the original measurements for the original grill plates which could be used?
    2. Where (on the internets) could I go to have JBL 4343 grill plates printed in high quality? I assume that you DIY'ers don't do this at home?
    3. What are the plastic nuts that attach the grill to the speaker called in English, please? Need these as most of them are gone.



    If nobody has a file for the grill plates, I can get the measurements for the 4343 grill plates from this thread and make a file in Photoshop which I'll upload for everyone to use.

  7. #7
    Heather [Senorita member] hjames's Avatar
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    Pretty sure I had a pair of logo/foilcals made for my 4341 grills by ebay member sign--shop

    http://myworld.ebay.com/sign--shop?_...p2047675.l2559

    I think he sells the mounting stuff for them as well



    Quote Originally Posted by DingDing View Post
    Hi, got a few more questions.


    1. Does anyone have a file with the original measurements for the original grill plates which could be used?
    2. Where (on the internets) could I go to have JBL 4343 grill plates printed in high quality? I assume that you DIY'ers don't do this at home?
    3. What are the plastic nuts that attach the grill to the speaker called in English, please? Need these as most of them are gone.



    If nobody has a file for the grill plates, I can get the measurements for the 4343 grill plates from this thread and make a file in Photoshop which I'll upload for everyone to use.
    2ch: Oppo, JoLida 502CRC, JBL L212, 18ti,240ti; Heath AS101, Von Schweikert VR4
    7.1: Oppo BDP103D, B&K, UREI 809A, JBL B460

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    JBL vintage badges for speaker grills

    Thank you, hjames, not exactly cheap, but they look very good and attach magnetically according to his listing. Seems like he makes them from aluminum.

    Posting a screenshot for reference if anybody else find this in the future and his listing is gone.


    And yes, he also has grill pegs for vintage JBL speakers.


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    You can improve by replacing T-nuts with hurricane nuts. In a hurricane nut is called rampamuff.

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    4343 Info..

    Hi DingDing,

    When you came to the "Technical Help" section of the forum, did you see '4343 Information' at the very top of the page? EXTENSIVE info gathered by
    'hjames'. Heather has found all the good stuff on these monitors. I also suggest going to the library and getting the Professional Series spec's - a 4 page brochure type Specification manual. Also the Crossover Network 3143 for wiring [if you have to go that far, but I think Guido went through it!]
    Search this forum and the DIY Forum. There is LOTS to be found if you look! Enjoy and "take your time"... you'll end up with a fine speaker!


    DogBox

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    Yep, those would work and the quality is quite good. You can see there is a "make offer" option, so ask for a package price, maybe you can get them a bit lower, and let him know its for Rolf's speakers, might help.

    Bart
    When faced with another JBL find, Good mech986 says , JBL Fan mech986 says

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    Quote Originally Posted by more10 View Post
    You can improve by replacing T-nuts with hurricane nuts. In a hurricane nut is called rampamuff.
    Thank you. If I didn't already buy a set of 32 new t-nuts and allan key screws I would go with your advice, but I had already pulled the trigger on those.

    Quote Originally Posted by DogBox View Post
    Hi DingDing,

    When you came to the "Technical Help" section of the forum, did you see '4343 Information' at the very top of the page? EXTENSIVE info gathered by
    'hjames'. Heather has found all the good stuff on these monitors. I also suggest going to the library and getting the Professional Series spec's - a 4 page brochure type Specification manual. Also the Crossover Network 3143 for wiring [if you have to go that far, but I think Guido went through it!]
    Search this forum and the DIY Forum. There is LOTS to be found if you look! Enjoy and "take your time"... you'll end up with a fine speaker!

    DogBox
    Hi DogBox,

    I've spent quite a few hours reading through that thread and the resources it links to now. To be honest, some of it, and especially everything that has to do with passive x-over designs go way, way above my head. However, this is a fine forum with a lot of great content, and I apologize about not reading more before I started posing all these questions, as I see that many of them have been answered thoroughly in the past. It was a case of excitement about the loudspeaker restoration project and information paralysis as there is so much here.

    I'll take on your advice and do this in baby steps. Looks like doing the veneer can be quite the task, but have found a lot of advice against the common pitfalls and what products that yield the best result.

    I thought my 4430's were good, but 4343 raise the bar even further! They sound absolutely spectacular! I'll look into another active crossover than the original 5235 with 4343 cards (which I use now) to see if I can push them even further! But as you say; take my time, and first things first; the restoration job, haha!


    Quote Originally Posted by mech986 View Post


    Yep, those would work and the quality is quite good. You can see there is a "make offer" option, so ask for a package price, maybe you can get them a bit lower, and let him know its for Rolf's speakers, might help.

    Bart
    Hello, and thank you for the tip. I'll probably buy two new l-lpad signs and a pair of signs for the grills as well as a bunch of those grill pegs to hold them in place, and will write him an email asking for a discount if placing an order for so many items. I'll mention that they're Rolf's speakers, but I don't want to make it look like I take advantage of his good reputation with the community either.

  13. #13
    Heather [Senorita member] hjames's Avatar
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    Hello again, DingDing!

    A couple of us have worked through various active crossovers and maybe this could save you some time and money.
    I started with the JBL UREI crossover and wound up using the Ashly XR1001 crossover.

    Its fairly quiet, it has knobs you can set the crossover point with, instead of having to build little circuit cards like the 5234,
    and its pretty affordable. I used one with my 4341 Monitors, I know Phil (BMWCCA) uses one with his 4345 Monitors, and I know some other folks have had good luck with them as well.

    Oh - they are reasonably priced, too!

    Good luck with your musical fun!



    Quote Originally Posted by DingDing View Post
    Thank you. If I didn't already buy a set of 32 new t-nuts and allan key screws I would go with your advice, but I had already pulled the trigger on those.

    Hi DogBox,
    I thought my 4430's were good, but 4343 raise the bar even further! They sound absolutely spectacular! I'll look into another active crossover than the original 5235 with 4343 cards (which I use now) to see if I can push them even further! But as you say; take my time, and first things first; the restoration job, haha!
    2ch: Oppo, JoLida 502CRC, JBL L212, 18ti,240ti; Heath AS101, Von Schweikert VR4
    7.1: Oppo BDP103D, B&K, UREI 809A, JBL B460

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    Quote Originally Posted by hjames View Post
    Hello again, DingDing!

    A couple of us have worked through various active crossovers and maybe this could save you some time and money.
    I started with the JBL UREI crossover and wound up using the Ashly XR1001 crossover.

    Its fairly quiet, it has knobs you can set the crossover point with, instead of having to build little circuit cards like the 5234,
    and its pretty affordable. I used one with my 4341 Monitors, I know Phil (BMWCCA) uses one with his 4345 Monitors, and I know some other folks have had good luck with them as well.

    Oh - they are reasonably priced, too!

    Good luck with your musical fun!
    Hi again, hjames

    Thank you for your input.

    Yes, Ashly XR1001 came on the radar yesterday as I was browsing through a lot of posts, including yours, on the forums. Found a used unit on a Norwegian site for second hand gear, contacted the seller and actually bought it a short while ago based on all the praise it got here, haha. It'll come by mail in one of the following days. Will try to use it to do active crossover with 4430 as well!

    Have been thinking about getting something like miniDSP 4x10 HD for 4430 earlier and do it all in the digital domain, but seems like XR1001 is a good starting point, and since it's fairly quiet, it's all good. Very nice to have the added flexibility of the crossover knobs.

    Next up might be to try those Crown amps for the woofers, since there seems to be some controversy regarding their performance on the highs and midrange. New amps have to wait until later though because I've exceeded my budget by quite a lot with buying the 4343's, but couldn't resist the opportunity as 4 way JBL studio monitors are few and far between here in Norway it seems.

  15. #15
    Senior Member Odd's Avatar
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    Good to see another enthusiast with 4-way JBL monitor.
    There is more than one would think of them here in Norway.

    Mine has diy enclosure with 2235, 2123, 2450, 2405 and CC crossover designed by 4313B
    Crossover was a big improvement. Thanks to 4313B.

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