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

[vifa32144]

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

[boputnam]

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... :yes:

[vifa32144]

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

[Rex Mills]

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

[boputnam]

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... :spin:

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.

[badman]

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!