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Thread: JBL 12'' 123A-3 and 123A-1 uses

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    JBL 12'' 123A-3 and 123A-1 uses

    What is the difference between the JBL 123A-1 and 123A-3 twelve inch woofers, and what cabinets were they used in?
    Gary Miles

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    Senior Seņor boputnam's Avatar
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    Hey, Gary...

    The infamous L100 series, as per the attached.

    As you can see, the gap on the 123A-3 is slightly larger at 0.048-in, versus the 0.044 for the 123A-1 (therefore different recone kits).

    Most importantly, the 123A-1 is a positive transducer, opposite the JBL "negative" convention as is the property of the 123A-3 (and 2213H, recommended replacement). There's plenty to read on polarity throughout Don's World...
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    Last edited by boputnam; 02-23-2004 at 10:08 AM.
    bo

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    Reply for JBL 123A-1 and 123A-3 woofers

    If that is the case, from the crossover both would still be connected as the woofers positive and negative terminal posts, right?
    Gary Miles

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    I think what Bo is saying, if you can't view the pdf files, is both the 123A-1 and 123A-3 where both L 100 woofers used in 2 different series of that loudspeaker. One woofer is in oppisite polarity to the other. How you hook them up depends on what xover you are using
    Rex Mills

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    Senior Seņor boputnam's Avatar
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    Re: Reply for JBL 123A-1 and 123A-3 woofers

    Originally posted by vifa32144
    If that is the case, from the crossover both would still be connected as the woofers positive and negative terminal posts, right?
    I'm confused...

    If you've got the:

    L100 - connect the 123A-1 Red post to GRN wire (as marked on the schematic). Do not be confused that the GRN wire actually connects to the Black cabinet binding post - that's the way JBL engineered it.

    L100A - connect the 123A-1 Red post to GRN wire. In this case, the GRN goes to the Red cabinet binding post.

    L100A (Late Model) - connect the 123A-3 Red post to GRN wire. In this case, the GRN goes to the Red cabinet binding post.
    bo

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    Some measured specs

    Couldn't get the chart to paste right, so It's a comparison of a pair of 123A-1 and 2213 (alnico) which should be equivalent to 123A-3. It's entirely possible that the 2213s show the higher Qes (and Qts) and lower Le as a result of lost motor strength from demagging. For my purposes, this is actually desirable, so huzzah!
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    Quote Originally Posted by boputnam View Post
    I'm confused...

    If you've got the:

    L100 - connect the 123A-1 Red post to GRN wire (as marked on the schematic). Do not be confused that the GRN wire actually connects to the Black cabinet binding post - that's the way JBL engineered it.

    L100A - connect the 123A-1 Red post to GRN wire. In this case, the GRN goes to the Red cabinet binding post.

    L100A (Late Model) - connect the 123A-3 Red post to GRN wire. In this case, the GRN goes to the Red cabinet binding post.
    I realize that this post is ancient, VERY ancient but may be in some small part responsible as a contributing factor for a modicum of the seemingly endless confusion regarding this subject, especially for someone doing a quick search for the answer to "how do I hook up my L100 woofers?"

    That is my motive for the post, not to nitpick with an 11 years old thread; I have been actively seeking the definitive answer for this age old question as of late myself. A new goal for me is to bring a final resolution and clarity to this matter before I die!

    THERE IS NO GREEN WIRE USED FOR THE BINDING POST FEED INTO THE BOX, CONNECTING AMPLIFIER OUTPUT TO THE NETWORK ON EITHER VERSION OF THE L100A. The L100As (both "A" and "A" (LATE) employ a RED wire to the RED post and a BLACK wire to the BLACK post. They are also cut aggravatingly short (they are the same RED and BLACK faston terminated pair as they used to hook up the tweeter, so keep this in mind when you upgrade binding posts, you don't have a lot of leeway here. With your network to woofer pair (the GREEN and BLACK) there's so much extra they had to fold it back twice and zip tie it! Same for the pair to the mids. Keep this in mind when re-capping or again, changing out binding posts, there's only and inch or so to work with, especially if you are stripping and soldering your connections. Could really be a pain if all you are doing is a post upgrade and don't want to pull the network, definitely measure twice and cut once.

    The woofer feed wire(s) change back to GREEN and BLACK (like the early days) at the network, coming off the solder terminal lugs where the RED and BLACK wires terminate from the binding posts. This switch follows JBL convention: the GREEN wire to woofer is soldered to the lug where the RED binding post wire terminates and the BLACK wire to woofer is soldered to the lug where the BLACK binding post wire terminates.

    ALL "switching" to account for which woofer is used or which ambiguous "tech sheet" you are working from is done at the woofer's hookup points (spring loaded terminals).

    THIS APPLIES ONLY TO THE N100 NETWORKS WITH RED AND BLACK TWEETER WIRES. If by chance you have a late model L100 with the YELLOW/YELLOW BLACK tweeter wires then all bets are off!

    I'm sure that before this ink dries someone will come with an oddball example built during the switch but that will be an anomaly. I am sure my information is accurate for the models with the N100s as indicated

    Good luck to all!

    Thomas

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