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Thread: JBL 4345 L-pad HELP

  1. #1
    Member vannozzi's Avatar
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    JBL 4345 L-pad HELP

    HI All,

    I bought the 6 original JBL 4345 L-pads that were for sale on Ebay a while back from the guy in France.

    The question I have is which L-pad goes to which driver.

    One set of L-pads is marked in pencil 1,2,3, but I don't know for sure which goes to which.

    The L-pad that is marked "1" has a green wire, a black wire & a an orange wire.

    The L-pad that is marked "2" has a brown wire, a red/white stripe wire, & a white/black stripe wire.

    The L-pad that is marked "3" has a red wire, a yellow wire, & a blue wire.

    I would "assume" that the L-pad marked "1" would be mounted on the top of the "foil-cal", and would go to the 2405 High frequency tweeter, and that the L-pad marked "2" would go to the 2421 horn, and the L-pad marked "3" would go to the 2122h midrange speaker.

    But you know what happens when you "ass-u-me" things!

    I would like to keep the L-pads in the original order even though I have had custom passive crossover networks made.

    If anyone knows for sure which L-pad goes to which driver, I would appreciate it if you could let me know.

    I have ordered: 4345 L-pad "Foil-cals" and knobs, JBL Blue grill cloth, JBL 4345 speaker grill emblem plates, and acoustic lenses from Kenji.

    Thanks, Mike Vannozzi

  2. #2
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    A Google search of "L-Pad wiring" turned up this thread

    http://www.audioheritage.org/vbullet...5-L-pad-wiring

  3. #3
    Member vannozzi's Avatar
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    Thanks Jeff

    Thanks Jeff, but that post shows aftermarket L-pads. I'm looking to find out the placement of the original L-pads. Cheers, Mike

  4. #4
    Administrator Robh3606's Avatar
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    Why don't you just hook up a driver to them and figure it out?? It's not like you can do any damage just use the 2122 as the Guinea pig.

    Rob
    "I could be arguing in my spare time"

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    Quote Originally Posted by vannozzi View Post
    Thanks Jeff, but that post shows aftermarket L-pads. I'm looking to find out the placement of the original L-pads. Cheers, Mike
    The schematic shows how they are wired, original or aftermarket.

  6. #6
    Member vannozzi's Avatar
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    L-pad wireing

    I don't think you guys are understanding my question.

    I know how to hook up the L-pads into the crossovers/ drivers.

    What I am trying to find out is which L-pad, with the wire colors that I outlined earlier, goes to which driver in a stock JBL 4345.


    I just want to keep the placement of the L-pads as they were in an authentic 4345.


    I understand that I can probably mix up the L-pads with different drivers, and it probably wont make a difference on how the components function.


    But I don't want to do that.

    I want to install the original L-pads in my JBL 4345 clones, in the same physical location in the cabinet, and conected to the same drivers as an original JBL 4345.

    Sorry for the confusion.

  7. #7
    Heather [Senorita member] hjames's Avatar
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    The L-Pads mount to a little sub-panel that mounts in the cabinet on the baffleboard behind the foilcal.
    Do you actually have that original subpanel and attached wiring harness?



    Quote Originally Posted by vannozzi View Post
    I don't think you guys are understanding my question.

    I know how to hook up the L-pads into the crossovers.

    What I am trying to find out is which L-pad, with the wire colors that I outlined earlier, goes to which driver in a stock JBL 4345.


    I just want to keep the placement of the L-pads as they were in an authentic 4345.


    I understand that I can probably mix up the L-pads with different drivers, and it probably wont make a difference on how the components function.


    But I don't want to do that.

    I want to install the original L-pads in my JBL 4345 clones, in the same physical location in the cabinet, conected to the same drivers as an original JBL 4345.

    Sorry for the confusion.
    2ch: Oppo, Acurus RL-11, JBL 240ti, Heath AS101, Carver TFM-25,Von Schweikert VR4
    7: Oppo BDP103D, B&K, UREI 809A, JBL B460,

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    Member vannozzi's Avatar
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    L-pad sub panel

    Hi hjames,

    No, I didnt receive the panels with the 4345 L-pads that I received from the Ebay purchase, only the 6 L-pads with sodered on color coded wires from an original JBL 4345 crossover network.

    I will wait to receive the "Foil-cal" plate that I ordered from Kendrick Sound, and use the plate as a template to drill the holes in the speaker cabinet, and fabricate the mounting panel for the L-pads.

    I'm just trying to find out which original L-pad wires go to which driver. The "Foil-cal" plate will indicate the position of the L-pads in the cabinet, and which L-pad will be on top, in the middle and on the bottom, and which driver that L-pad will be conected to.

    The only question is the colored wires, and to which driver they are conected.

    So, if someone has a photo of the back of the L-pads mounted in a 4345, or perhaps knows which colored wires are supposed to go to which driver, that information would be appreciated.

    Thanks, Mike

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    http://www.jblproservice.com/pdf/Network Schematics/3145 Network.pdf

    Page 2 shows the R201/202/203 positions and tap assignments, but not the wire colors. That's about as close as you're going to get.

    That said, if building replica 4345s was my goal, I think I'd buy new L-Pads instead of some vintage units.

  10. #10
    Member vannozzi's Avatar
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    RE: JBL link

    Hi Jeff, the JBL link doesn't seem to work. Thanks, Mike

  11. #11
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    Quote Originally Posted by vannozzi View Post
    Hi Jeff, the JBL link doesn't seem to work. Thanks, Mike
    I'm having a lot of trouble with this site as far as formatting my posts.

    I type each sentence with a page break between them, and the site runs them all together without so much as a space between the period at the end of one sentence and the first word of the second sentence.

    For some reason, the site deemed it necessary to append the first word (Page) of my sentence following the link, to the link.

    I tried to edit it, but it evidently didn't take.

    Here it is again:

    http://www.jblproservice.com/pdf/Net...%20Network.pdf

  12. #12
    Member vannozzi's Avatar
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    RE: 3145 schematic link

    Hi Jeff,

    I was able to open the link this time.

    Thanks very much for trying to help me.

    I apreciate you.

    I have seen this schematic before, and it's mostly unreadable.

    When I was looking for the original schematic for the JBL 3145 crossover, this was all I could find.

    So I printed it out in the highest resolution mode, and Then I tried to blow it up so I could read it.

    You can't read it.

    I think it was originally a hand drawn, large blueprint sized sheet that has been reduced down to an 8.5 X 11 sheet.

    Anyway, thanks for your effort.

    I think the only way I will be able to obtain the information that I'm looking for is for someone to take a photo of the L-pads mounted in the original cabinets.

    If not , I'll just put the L-pad marked "1" in pencil in the top position, 2 middle, and 3 bottom, and wire it accordingly.

    Kind regards, Mike

  13. #13
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    I can read it just fine. It is the schematic for the 3145, the original JBL schematic for the 3145.

    R201 MF

    R202 HF

    R203 UHF

    Terminals

    1 at 2 o clock all L-pads

    2 at 9 o clock all L-pads

    3 at 5 o clock all L-pads
    Attached Images Attached Images  

  14. #14
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    Try this.
    Attached Images Attached Images  

  15. #15
    Member vannozzi's Avatar
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    RE: L-pad numbers

    Hi Jeff,

    The terminals are numbered on each L-pad and are cast into the back porcelin part of each L-pad .


    This still won't tell me which colored wires go to which driver circut.

    CLUES:

    1) One set of the wires from the 3 L-pads are zip tied together in a way that would indicate the wires would have to go either left or right.

    2) The wires are sodered in a sideways direction. (still could go either left or right.)

    3) In the first set of L-pads, the wires are slightly bent in a way that indicates that they would go downwards, and have been held in this position by the zip tie.

    This indicates that the L-pad marked "1" would be in the top position, which is the L-pad with the green, black and orange wires.

    "2" would be in the second position which is the L-pad with the wire colors that are red, brown, and white with black stripes.

    "3" would be in the bottom position which is the L-pad with the wire colors of: red, white, and blue.

    4) In the second set of L-pads, the zip tie is missing, and the wires are a jumbled mess, and there are no pencil marks indicating 1,2,3, like the first set.

    There is a kink where all of the wires line up together, and this is where I believe an old zip tie used to be.

    So, I just put on a new zip tie where the old one was, and the existing bending of the wires now indicate that like the other set,

    the L-pad with the green, black, and orange wires would have to be installed in the top position, and the other L-pad sets fall into place as middle and bottom.


    So the answer to my question has revealed itself to me.

    Thank you to all who participated in this post for your help and imput.

    Best wishes for a Happy New Year to all.

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