Trashed JBL L36 Decade Restoration - I Need Your Help!

Discussion in 'The Lansing Legacy' started by MCM_Fan, Mar 30, 2016.

  1. MCM_Fan

    MCM_Fan AK Subscriber

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    I recently picked up a pair of pretty trashed out JBL L36 Decade speakers on the cheap and based on everything I've read, they are worthy of restoration. These have the oak veneer and the burnt orange grill cloth. Of course the veneer has chips and the obligatory plant rings and the grills are stained, snagged and have holes. That part I can handle. BTW, I know I could change the grill cloth color to one of the more common black, brown, blue or beige colors, but it was the burnt orange grill cloth that caught my attention. It's much less common on the L36 Decades, and a good match for my other MCM decor. Plus, I like being a little different. I already have plenty of other speakers with black, brown and beige grills. This will be my first orange pair.

    The drivers are all present, but have some problems. Both LE25-4 tweeters have pushed in dust caps, but otherwise seem fine. Both 125A woofers will need refoamed - again not a big deal (but I will have some questions when I get around to it). The big problem is one of the LE5-6 midrange drivers is damaged and will need to be repaired or replaced.

    The paper cone is torn and not likely repairable and the aluminum dust cap it completely pushed in. The DCR measures right at spec at 6.1 ohms. So, should I recone the existing driver or replace it with a new/used one? I've never done a recone before, but think I can manage if I go slow. Then it becomes a question of cost/value. I can get a recone kit from The Speaker Exchange for $30 + shipping, but it comes with a paper dust cap. I want an aluminum dust cap to preserve authenticity and match the other speaker. I can get an aluminum dust cap from Midwest Speaker Repair for $7.50 + shipping. So, assuming I don't mess things up, I can recone the damaged LE5-6 midrange for about $46 in parts and shipping. I can get a new "replacement" midrange from Simply Speakers for $59.95 with free shipping. The final option is a used LE5-6. Of course, prices vary, but it looks like I should have no problem getting one in excellent+ to mint- condition for about $50 - $60, maybe less if I'm patient.

    Given that all three options cost about the same (assuming I could sell my damaged LE5-6 for $10 - $15 if I elect to go for a new or used replacement), what would you recommend? Would this be a good driver to attempt my first recone? Is it worth the effort, or should I just go for a replacement? If so, new "equivalent" driver or used genuine JBL LE5-6?

    Thanks in advance. More questions and pics to follow...
     

     

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  2. elnaldo

    elnaldo Addicted Member

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    "recone" a speaker, if you have the right parts, is easy. But it seems expensive up there (I live in Buenos Aires, a paper cone of that size costs like $1 or 2 down here. A dust cap will cost you like $0.5/0.75. A foam edge for a small speaker costs $1 or $2) I've done it several times, even on 8" speakers, keeping the spider and VC untouched, just cutting the old cone and gluing around the original VC. Removing VC and spider, and install all new parts is not that easy, but if you are skilled, not difficult.

    I'd get an used item if you can probe it's original never repaired, it will be as old as yours, it should perform as your good one, but only if you find it cheap. If it costs like a new driver, I'd get a new pair and sell yours.

    Or, try to find a chinese supplier for the cone. Perhaps you get it for 1/10 of the price.

    Are you sure it's not repairable? can you upload a pict? Perhaps removing the dust cap, centering the VC, and gluing the old paper can work.
     
    Last edited: Mar 30, 2016
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  3. jmcturnan

    jmcturnan New Member

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    Hi, I just finished a complete restoration of a pair of L100s: new walnut veneer, new foam cube grills (blue), recone of the 123a woofers, complete crossover rebuild. Tweeters and mids were ok.

    I opted to have Orange County Speakers do the 123a because i read the voice coils have a very narrow gap that is trickier than most. My experience with them was stellar. The cost was significantly higher than diy, but it also included a recharge of the magnets and a warranty.

    I'm happy to share anything else if you have further questions.

    John
     
  4. MCM_Fan

    MCM_Fan AK Subscriber

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    The recone kit I mentioned from The Speaker Exchange for $30 also includes a replacement voice coil and spider. Here's a description of what's included:

    Product Description
    JBL LE5-2, LE5-8, LE5-9, LE5-10, LE5-12 Aftermarket Recone Kit 8 ohm. Difficult DIY repair! Parts specifications:

    • Cone: 4″ JBL LE5 cone
    • Voice Coil: Kapton with .870″ inside diameter, .450″ form length, .125″ windings width, 8 ohm
    • Flat Spider: with .750″ VC opening, 2.4″ outside diameter . spider must be gently opened to fit larger vc. see note below.
    • Dustcap: 1.6″ Paper dome with lip up
    • Gasket: reuse original gasket
    • Pigtails, shims and instructions are included.
    You will also need glue and epoxy which are sold separately.

    Here's a photo:

    JBL_LE5-6.jpg

    It's torn very close to the lead wire and I can't get at the back of the cone in that area to glue it. If I'm going to put the time and effort into restoring these speakers, I wan to do a first reat job so they look, and sound like new (or as close as possible).
     
    Last edited: Jul 28, 2017
  5. elnaldo

    elnaldo Addicted Member

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    I see..those are sealed back... I'd try to pull the loosen part with some dentist -like hook and apply a bit of paper glue to hold it in place. Once you don't need the hook anymore, you could paint the edges with paper glue to glue completely. Masking tape could also help to hold the paper and glue part by part.

    Replacing all the parts is easier than repair. You need to pay attention at the VC height on the magnet. Some speakers have the VC at the magnet level but some don't.

    If you are worried about the appearance, you could recone it. But I'd try to glue it, check it's working, and leave the re cone or replacement as the last task of your restoration.
     
  6. ZOOM

    ZOOM Well-Known Member

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    If you recone it, it becomes a totally different speaker, and the chances of it being a suitable replacement to the original are very slim.
     

     

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  7. MCM_Fan

    MCM_Fan AK Subscriber

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    Really, why is that? I've never reconed a speaker, but I thought the point of reconing one was to restore it to factory specs/performance. JBL used to offer recone kits for the LE5 midrange, but they are long out of production. If you can find a NOS genuine JBL LE5 recone kit, it runs 3x - 4x the cost if a used replacement driver.
     
  8. elnaldo

    elnaldo Addicted Member

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    The fact is those are not factory parts, and changes in the mass, VC position, spider hardness and so, can modify the responses, specially in small drivers as mids or tweeters. That's why I usually try to let the original VC - spider assembly untouched, and glue a new cone on that assembly.

    The times I had to recone a tweeter (burned VC) , I had to modify the crossover to get the right response.
     
    Last edited: Apr 4, 2016
  9. MCM_Fan

    MCM_Fan AK Subscriber

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    I guess I misunderstood the purpose of recone kits. I thought the supplied parts were intended to match the manufacturer's specs. The recone kit I linked above from The Speaker Exchange lists the cone as:
    • Cone: 4″ JBL LE5 cone
    To me, that implies a genuine JBL part. I suppose I can call and ask, but if reconing the LE5 will require redesigning the crossover, count me out. I'll just keep looking for a used driver in good condition. I posed a WTB in Bartertown.
     
  10. elnaldo

    elnaldo Addicted Member

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    If they are factory parts, or exact replacements, the driver should perform reasonably close to the original...
     
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  11. MCM_Fan

    MCM_Fan AK Subscriber

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    I have a temporary solution to my midrange problem. I have JBL LE5-9 midrange from a 4411 that I can use until I find a proper LE5-6 replacement.

    JBL_LE5-9_LE5-6.jpg
     
    Last edited: Jul 28, 2017

     

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  12. bandg69

    bandg69 AK Subscriber Subscriber

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    The parts list States aftermarket. Aftermarket is not original.
     
  13. MCM_Fan

    MCM_Fan AK Subscriber

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    A few photos to document the process:

    Before - Grills On:

    JBL_L36_Decade_Before_1.jpg

    Before - Grills Off:

    JBL_L36_Decade_Before_2.jpg

    Before - One Tweeter:

    JBL_L36_Decade_Before_3.jpg

    Before - Other Tweeter and Torn Midrange:

    JBL_L36_Decade_Before_4.jpg

     
    Last edited: Jul 28, 2017
  14. MCM_Fan

    MCM_Fan AK Subscriber

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    Before - The Cabinets:

    JBL_L36_Decade_Before_5.jpg

    JBL_L36_Decade_Before_6.jpg

    JBL_L36_Decade_Before_7.jpg

     
    Last edited: Jul 28, 2017
  15. GordonW

    GordonW Speakerfixer Subscriber

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    Actually, no, I've done a lot of these LE5 recones. It works with the original crossover just fine. In fact, some of the excess sibilance of the original is removed, by the aftermarket kit.

    Regards,
    Gordon.
     
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  16. Binkman

    Binkman Addicted Member

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    kids with fingers? LOL... seen quite a few.. (what does this button do daddy?) as noted you may be able to suck out the indent. You can cut the cone off and reveal the coil and it may provide more khz region, too as long as the cone is resealed / elnaldo's suggestion. That tiny indent is okay, too on the second tweeter. just ignore it though not perfect should perform as long as the unit is good.
     

     

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  17. turboyam

    turboyam The Kenwood fan!

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    For the tweeter, use a vacuum cleaner with a funnel. Small end of funnel gently closer and closer to the dome till it's sucked out.
    Works every time.
     
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  18. MCM_Fan

    MCM_Fan AK Subscriber

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    Thanks! Ill give that a try. All my other speakers either have dome or EMIT tweeters, so I've never had to fix a dust cap anywhere near this small before.
     
  19. MCM_Fan

    MCM_Fan AK Subscriber

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    Thanks, good to know!
     
  20. MCM_Fan

    MCM_Fan AK Subscriber

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    Just a quick update (more to follow) and a question.

    Many parts have arrived - burnt orange grill cloth from Huntley, a single replacement grill peg from eBay seller sign-shop, replacement dust caps for the LE25 tweeters from Speaker Exchange. I also won a nice replacement LE5-6 on eBay this morning for less than the cost a a recone kit and less than half the price of a new, aftermarket replacement. I'm also finalizing my cap selections for the crossover rebuild and will place my orders for those tonight.

    But, most of my work so far has been on refinishing the cabinets. LOTS of sanding involved. I went slow, VERY slow, on the first one and did all the sanding by hand, starting with 120 grit on the top and bottoms, which was necessary to remove the scratches, pot rings, stains, etc. I followed that with 150 grit, then 220 grit and finally 320 grit. For the sides, I started with 150 grit to remove the existing finish, followed with the same 220, 320 progression. The first speaker is done and ready for the new finish. The second one, I have completed the top and bottom (always the most work due to the scratches, pot rings, etc.). Based on what I learned on the first one, I felt comfortable using my orbital sander on this one - at least for the rough sanding. I'll still do the 220 and 320 by hand.

    In any case, that leads me to my question. After I had the top and bottom prepped on the first speaker. I took it with me to my local Rockler store to investigate my finish options. I left the sides of the cabinet in their original state, so they could be used as a reference for matching the new finish. The original finish on these has a bit of an amber tint, but no gloss at all. They just looked like natural wood with a bit of stain to get the amber tint. Most JBL restoration threads I've read recommend 2 or 3 coats of Danish oil followed by a paste wax (like Minwax). So, that was how I was leaning when I arrived at Rockler. The salesman was very helpful and confirmed that Danish oil follow by a good furniture grade furniture wax would be a good choice. Although they had stains that would match the original finish, he said Danish oil can't be applied over stain and that I'd need to go with either a spray on lacquer (like Dreft) or a satin polyurethane, but both of those would add more sheen to the final finish. He recommended I go with Watco Golden Oak Danish Oil followed by the Minwax.

    I bought both those items, but decided I wanted to test them on a scrap of white oak before I committed to finishing my cabinets. I prepped the test piece in the same manner as the speaker and followed the instructions on the can. The result is something that looks LIGHTER, with more of a yellow tone than the plain mineral oil I use when wiping the dust off the cabinets after sanding - definitely not close to the original amber finish. The salesman at Rockler did show me what the Golden Oak looked like, but he used a scrap of red oak, not white oak like the original veneer, I think that may have influenced the results and his recommendation to go with the golden oak. I don't require an exact match, as I am completely removing the original finish on all four sides down to the bare veneer, but now I'm thinking I should maybe just go with the Watco Natural Danish Oil, or maybe even the Watco Cherry Danish Oil to get closer to the look I want. I've read other threads where the Watco Natural has been used on JBL oak cabinets and most seem to be pleased with the result. Would that give me a look similar to what I see when I wipe the cabinets down with mineral oil to remove the dust?

    So, any recommendations? Should I just go with the Watco Natural. Should I try the Cherry on my test piece? Should I skip the Danish Oil and go with an amber stain that will more closely match the original finish and then figure out what to do for a top coat? The nice thing about the Danish oil is it's real easy to apply, penetrates and protects the wood. The Danish oil followed by the wax provides a nice hand rubbed finish that looks like fine furniture that is easily renewed without stripping and refinishing again in the future.

    So, what do you experts recommend. I'm putting the cabinet work on hold today until I figure out how to proceed. I'll work on installing the new grill cloth today and ordering my crossover caps.
     

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