Page 1 of 2 12 LastLast
Results 1 to 15 of 20

Thread: 4311 Restoration

  1. #1
    Senior Member Mike F's Avatar
    Join Date
    Feb 2011
    Location
    Montreal, Canada
    Posts
    265

    4311 Restoration

    My vintage JBL journey continues. This time it`s led me to a pair badly abused and neglected pair of WX-As.
    These were originally installed in a regional Canadian Broadcasting Corporation studio but likely sustained the damage after being decommissioned.
    As you can see, the cabinets were in a sad state.
    The drivers didn't fare much better. One 2213 had a large tear in it`s cone accompanied by a footprint and one of the LE25s had the familiar finger modification done to its dome. Thankfully, the LE5-2s were unharmed.
    I managed to undo the LE25 finger mod successfully using the water and suction method, but another woofer had to be sourced. The grille frames were in good condition but the cloths were not.
    Attached Images Attached Images    

  2. #2
    Senior Member Mike F's Avatar
    Join Date
    Feb 2011
    Location
    Montreal, Canada
    Posts
    265
    I`ve restored badly damaged JBL cabinets before, older models used much thicker veneers like back in the L36 era which gave you more to work with, but the veneers used in this vintage were noticeably thinner and therefore, less forgiving.
    These cabinets were beyond repair and needed a re veneering. The problem with that was, I`ve never done it before
    After some research, I thought I`d give it a try, the speakers couldn't possibly end up in worse shape than they re already in.
    Before the new veneer could be applied, deep scratches, gouges and bashed corners had to be repaired. What a long and dusty process that was but it needed to be done.
    I settled on the wood glue and iron method, bought some Black Walnut veneer and got busy.
    That too, proved to be quite the task but the result surpassed my expectations
    Attached Images Attached Images    

  3. #3
    Senior Member Mike F's Avatar
    Join Date
    Feb 2011
    Location
    Montreal, Canada
    Posts
    265
    With the veneering out of the way, I thought to myself:
    "I`m going to need some tall stands to get the Mids and Tweeters anywhere near a 37 inch ear level!"
    Sure one could always invert the cabinets and call it a day but sadly, my OCD would never allow for that, there was just no way that I could have gotten used to backward and upside down script, despite the sonic benefit.
    Since this pair will not be seated on a meter bridge any time soon and after a little brainstorming session I figured that with a slight baffle modification, I could achieve an optimal tweeter height and proper script orientation.

    Naturally I was concerned about the consequences of such a modification, particularly those of the Audio Gods and what they would have to say about messing with a classic design but I figured the pro`s outweighed the con`s and to keep the Gods possible wrath at bay, I made the mod completely reversible.

    The crossover and L Pad assemblies (3112a)were already removed waiting to be re capped and cleaned so it was a good time to make the move. I decided on separating the caps and L Pads and making new panels in order to avoid
    cutting up the original plate to clear the mid range enclosure sub-enclosure.
    That also made for more flexibility in terms of component and wiring choices.
    The new panels were made from .25" Baltic birch. A thin sheet of foam rubber was glued to the surfaces that contacted the interior baffle to eliminate vibration.
    Next up was the tricky part, boring the baffles for the L Pad knobs. I made a cardboard template for the positions of the 4 mounting holes preserving, the original spacings.
    The knob holes measured in at around 22mm, a large hole in a .75+ inch baffle. At a friends suggestion, a 7/8" Forstner drill bit was used for the task at hand. A few practice holes were drilled into some scrap wood prior to the real thing just to get a feel for things. That turned out to be time well spent, the holes are clean and straight!
    Attached Images Attached Images    

  4. #4
    Heather [Senorita member] hjames's Avatar
    Join Date
    Nov 2005
    Location
    NoVA - DC 'burbs
    Posts
    8,341
    Its looking VERY nice ...
    I hope you are planning to saw a round plug from scrap wood or a dowel or something to glue/plug the old pair of holes under the label-plate?

    Quote Originally Posted by Mike F View Post

    The crossover and L Pad assemblies (3112a)were already removed waiting to be re capped and cleaned so it was a good time to make the move. I decided on separating the caps and L Pads and making new panels in order to avoid
    cutting up the original plate to clear the mid range enclosure sub-enclosure.
    That also made for more flexibility in terms of component and wiring choices.
    The new panels were made from .25" Baltic birch. A thin sheet of foam rubber was glued to the surfaces that contacted the interior baffle to eliminate vibration.
    Next up was the tricky part, boring the baffles for the L Pad knobs. I made a cardboard template for the positions of the 4 mounting holes preserving, the original spacings.
    The knob holes measured in at around 22mm, a large hole in a .75+ inch baffle. At a friends suggestion, a 7/8" Forstner drill bit was used for the task at hand. A few practice holes were drilled into some scrap wood prior to the real thing just to get a feel for things. That turned out to be time well spent, the holes are clean and straight!
    2ch: Oppo, JoLida 502CRC, JBL L212, 18ti,240ti; Heath AS101, Von Schweikert VR4
    7.1: Oppo BDP103D, B&K, UREI 809A, JBL B460

  5. #5
    Senior Member Mike F's Avatar
    Join Date
    Feb 2011
    Location
    Montreal, Canada
    Posts
    265
    Quote Originally Posted by hjames View Post
    Its looking VERY nice ...
    I hope you are planning to saw a round plug from scrap wood or a dowel or something to glue/plug the old pair of holes under the label-plate?
    Oh absolutely, details of which will appear in the upcoming "Crossover" episode.
    Stay tuned

  6. #6
    Senior Member Mike F's Avatar
    Join Date
    Feb 2011
    Location
    Montreal, Canada
    Posts
    265

    Crossover

    The cross over was next in line. While newer cross over designs undoubtedly improve upon the systems response, I chose to stay with the all too simple original layout but with modern components.
    After some research, Clarity Caps were found to be considered a smooth sounding upgrade to the 35 year old originals so they were chosen.
    The L Pads cleaned up nicely and re used but the original wiring just had to go. It was replaced with 12 AWG twisted pair going from binding posts to cross over input and woofer input, 16 AWG twisted pair everywhere else.
    All fast-on connectors were crimped and soldered.
    The binding posts too were upgraded to a nice WBT type set that accepts more modern speaker cables.
    Some might think the re worked cross over a little over built but I figure that if it`s worth doing ,it`s worth over doing
    The new cross over and L Pad panels were reinstalled and lined up perfectly.
    The original panels L Pad mounting holes were plugged up and reinstalled back into their original locations.
    Attached Images Attached Images     

  7. #7
    Senior Member
    Join Date
    Oct 2006
    Location
    Ontario
    Posts
    219
    The veneering looks excellent! Where did you buy your veneer? Also, how did you repair the bad corner before veneering? (I'm working on a pair of L100T that could use new veneer but I've been patching the bad corners with epoxy wood filler with plans to stain or paint them.)

  8. #8
    Senior Member Mike F's Avatar
    Join Date
    Feb 2011
    Location
    Montreal, Canada
    Posts
    265
    Quote Originally Posted by tomee View Post
    The veneering looks excellent! Where did you buy your veneer? Also, how did you repair the bad corner before veneering? (I'm working on a pair of L100T that could use new veneer but I've been patching the bad corners with epoxy wood filler with plans to stain or paint them.)
    I bought the veneer from a local lumber yard that carries a more exotic variety of wood than your average big box renovation center.
    http://www.langevinforest.com/en

    The veneer I used was Black Walnut. It is quite light and relatively featureless in raw form but apply some Watco oil and the transformation is stunning as you will see shortly.
    Even though the cabinets were re veneered, light to moderate scratches were treated to some LePage`s wood filler.
    Gouges and corners were repaired with believe it or not, Bondo
    automotive putty.
    In most cases, several thin layers were applied and shaped, lots `o dust.

  9. #9
    Senior Member SEAWOLF97's Avatar
    Join Date
    Jan 2006
    Location
    PDX, ®egon
    Posts
    9,111
    I love seeing the vintage speakers regain their former beauty. JBL's of that era were very nicely crafted , hence their retention of value.

    (can't even see black)
    “If you think that’s the dumbest thing you’ve ever heard,
    just wait a couple minutes!”

  10. #10
    Member
    Join Date
    Aug 2006
    Location
    Cambridge, UK
    Posts
    94

    Lovely Piece of work

    Congratulations on a great job. The original mistreatment was extreme and it is great to see those classic speakers back in operation and looking like they should

  11. #11
    Senior Member Mike F's Avatar
    Join Date
    Feb 2011
    Location
    Montreal, Canada
    Posts
    265

    Grilles

    The original grilles were in a sad state. The cloth had begun to separate from the frames and there were several tears and holes in them. Luckily, the frames were solid.
    I had on hand some Navy and Electric Blue cloth from a previous project that never materialized but couldn't decide which to use, so I made another pair of frames and used both
    They turned out better than anticipated so I`m temped now to build a Black pair and a Tan pair, grilles for all seasons.
    Attached Images Attached Images   

  12. #12
    Senior Member Mike F's Avatar
    Join Date
    Feb 2011
    Location
    Montreal, Canada
    Posts
    265

    Stands

    Even with the new midrange and tweeter arrangement, it was difficult to find a pair of suitable, off the shelf stands. Most models are geared toward modern bookshelves that are all but useless for vintage JBLs, being too tall with too small a footprint. The closest to ideal that I came across were from Target Stands.
    They have some very nice, sturdy metal post models but at close to $500 a pair..........it was time for some more DIY.

    Aside from the substantial cost savings, building your own stands gives you the option of customizing critical dimensions to suit your requirements exactly.
    Due to my limited woodworking skills, tools and working environment (my kitchen), the design needed to be kept simple.
    I went with two 1/2" pieces of 12"x12" Baltic Birch panels sandwiched together to form the bottom plate, a single length of 3.25" square solid Cherry post supporting a 12" x 12", 3/8" thick top plate.
    The center post was offset a little towards the back just to give it a less boring appearance.
    Stabilization is accomplished with four, 1 and 5/8" long chromed large headed 1/4-20 threaded bolts mated to T nuts on all four corners.
    I also found a use for some JBL badges too. The stand height minus the spikes is 16" which bring the mids and tweeters to 36". Perfect!
    Attached Images Attached Images    

  13. #13
    Senior Member Mike F's Avatar
    Join Date
    Feb 2011
    Location
    Montreal, Canada
    Posts
    265

    End result

    So this is what they look like now
    Attached Images Attached Images    

  14. #14
    Senior Member Mike F's Avatar
    Join Date
    Feb 2011
    Location
    Montreal, Canada
    Posts
    265

    A few more pics

    A couple more
    Attached Images Attached Images    

  15. #15
    Senior Member Mike F's Avatar
    Join Date
    Feb 2011
    Location
    Montreal, Canada
    Posts
    265

    One more

    Attached Images Attached Images  

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. JBL L40 restoration
    By paulfromcamden in forum Lansing Product Technical Help
    Replies: 1
    Last Post: 07-08-2012, 03:51 PM
  2. 044 restoration
    By grumpy in forum Lansing Product DIY Forum
    Replies: 9
    Last Post: 10-15-2007, 08:16 PM
  3. L-96 Restoration
    By DMMD in forum Lansing Product Technical Help
    Replies: 28
    Last Post: 10-24-2005, 02:19 PM
  4. Restoration - Thanks Don !
    By Earl K in forum Forum Feedback
    Replies: 1
    Last Post: 08-14-2003, 05:09 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •