View Full Version : On a lighter note...(2123J-b test box)

08-13-2003, 04:14 PM
In anticipation of my next project, I finally got around to building a test box for the 2123J's Bo was so kind to broker me. No beating me up on the quility of the test unit, it was an hour and a half on the table saw and all scrap wood, and left over fglass. I want to drag all the stuff outside on the week-end and fire it all up. Hopefully these sound as good as I've read. I think I know now what the "B" in b stock means, I'll see if anyone else catches it.

08-13-2003, 04:21 PM
Can you see it?

scott fitlin
08-13-2003, 04:53 PM
Is that a Ding I see in the top part of the woofers outer frame?

08-13-2003, 05:05 PM
WRONG!!!!!.....lol..... Give you a hint, it's not cosmetic as such... go look at the pic of 2123 at JBL Pro.

scott fitlin
08-13-2003, 07:03 PM
Im stumped! your picture makes it look bigger than a 10" though! Probably another illusion on my part!

Mr. Widget
08-13-2003, 07:05 PM
Scott, take a look at the voice coil leads.

Ok maybe that is more than a hint:D

scott fitlin
08-13-2003, 07:07 PM
I dont know! I see the leads and they dont look perfect but on the JBLpro pictures you really cant see the leads, either!

Mr. Widget
08-13-2003, 07:11 PM
Shouldn't the leads point straight down between the flange bolts?

Ok, so this is a bit silly, but then again the name of the thread is:

On a lighter note...:D

Mr. Widget
08-13-2003, 07:23 PM
Hey Luxmanlover,

Over what frequency range will you be running these?

Will they be fed directly from an amp or will they be getting signal through a passive crossover network?

scott fitlin
08-13-2003, 07:23 PM
Duh, Im stupid today! Your right, now that you said it, I see it! Tricky one! :D

Alex Lancaster
08-13-2003, 07:53 PM
I still donīt get it, are they reman's, does it make any diff?


08-13-2003, 08:22 PM
I have gotten a couple of B stock items. 2035 and M209-8's. They seemed to have some rather insignificant cosmetic blemishes. Asside from that they worked just fine.


08-13-2003, 08:25 PM
subtle, but not necessarily bad... ;)

08-13-2003, 08:27 PM
So the leads are a little longer??? I woundn't sweat it.


08-13-2003, 09:00 PM
Yes the leads point at a 45 degree angle. However Giskard PMed me and informed me that "B" stock used to refer to returned items and that angled terminals are not uncommon (just unwanted in my case) so that makes me the stup, oh well, I'll live with it. As far as scale I think the weanie 17 L. box throws the scale out of whack. I attached a pic of the test box on my yard sub which has 2235's, it gives a better idea of scale. If the picture was better you would be able to see how much lighter in colour the 10's are in comparison to the 15's. Again kind of weird.
To answer Widget's, I'm not sure yet. Most apps using the 2313's cross them around 300-1200. I was lucky enough to find a couple of 525 active XO's So I'm going to try some different setting and see what happens. I was actually wanting to try crossing them a fair bit higher around 3000, but I'll see how it sounds I guess.

08-14-2003, 09:51 AM
Huh, looks like someone forgot they weren't loading the cone into an early style basket. Lots of the early 10" variants (LE10A, etc) had the terminals coming out of one of the basket ribs... so that would have been the appropriate location for the lead feed-outs in that case...

having almost done the same thing myself reconing a driver... :rolleyes: :D

Earl K
08-15-2003, 06:07 AM

The 2012 - the "Pro" divisions successor to the 2123 - has a basket that uses one of the 4 ribs to hold the terminals. Kellys' 2123j might have been a transitional product - a migration from the older basket style to the newer .

re; "B" models at the tent sale - my take is that these are all speakers that for one or another reasons, don't meet JBLs' QC standards. Some of those standards can be implemented "on the line" with simple Fs and Re tests. A few years back I bought a load of 2123h drivers from an earlier non-public "tent sale". Most of these 2123h mids have Fs figures that are about 10hz lower than the specified 75 hz .

regards <> Earl K

08-15-2003, 06:15 AM
The 2123J-B's I recieved had JBL QC control tags on them so I would hope they meet spec. This could be a chance to give measuring ts specs a shoot for the first time and find out.

Just did a quick check of Re ...8.4 ohms...a touch lower than spec but my meter might be off too. 8.7 is spec ?????? 16 ohm rating ....don't get it!

08-15-2003, 06:25 AM
A photogragh

08-15-2003, 08:10 AM
8.4 ohms DCR is well within the tolerance for a 2123J. Yes, the median DCR is spec'd at 8.7 ohms + or - 10%.

The style of basket does vary. Like others have posted, early LE10 and LE14 frames mounted the terminals on one of the ribs, which we refer to as being at 45 degrees. Later frames had a special mounting flange so the terminals could be mounted straight down, which we refer to as being at 90 degrees (I suppose 270 is technically correct but whatever...). When JBL replaced the metal push terminals with plastic push terminals, many of the transducers went back to 45 degrees.

At one point B stock did mean that it either didn't pass QC (usually for cosmetic reasons) or that it was a return. The 2245H's from the tent sale a few years back were definitely out of QC spec electrically and I had numerous discussions about that. Suffice it to say, those particular transducers in the typical 8 to 10 cubic foot enclosure tuned to the usual 25 to 30 Hz WILL perform as expected.