Hi JBL world. Another newbee, not deeply knowledgeable with JBL. I've just installed D123-A3's (corrected polarity) in my 4311B's. I was curious how the older alnico magnet woofers would sound in them. They're hooked up to a Sansui AU-717, and an old Shure ML 120HE. I kinda like the sound. But does this modification de-value the 4311B's?
ThanX
De-Value?
Why would they? The value is in the enjoyment of listening to them.
Audio is not a good hobby to collect to invest -- at least that is MHO.
Welcome to the forum!
-Storm.
I have no idea.Originally Posted by KenMiles
The D123 was designed for a specific purpose. That said, the 4311B was designed with the 2213H. You are on your own...
Did you model the woofers using their Thiele-Small parameters and the 4311B dimensions? What do your models say...?
bo
"Indeed, not!!"
It's 123A-3s presumably, no "D."
And there's no polarity issue to correct, I don't believe, but I'm not going there again, nope.
http://audioheritage.org/vbulletin/s...ad.php?t=12757
Swapping the drivers will only devalue them if you tell, of course.
Unless you hype the Alnico angle as making them more desirable, and some fool falls for it. "Fools," actually, 'cause it takes more than one to boost the selling price.
Send me the POS 2213Hs you took out, please....
Well, I started down that route too, Zilch, but then thought maybe the OP really meant the D123, an old-school AlNiCo motor transducer.
Indeed, if it is the 123A-3, the polarity is identical to that of the 2213H (these are both negative) so it should be connected as the 2213H was.
We need to know 'zactly what is going on...
Honestly, Bo, I Homer Simpson’d it. I'm unable to comprehend Thiele-Small parameters. My intelligence has holes, kinda like Homer’s doughnuts.
Hi Zilch.
Thanks for the heads up. You’re probably right about the ‘D’- I’m not inclined to take the woofer out to take a look. The 123-A3 woofer frame has the same robust design as the 2213H, with the large rectangular spokes.
On polarity, I defer to Homer. Homer connected a small battery to the posts and found the 2213H pushed outward with the positive to the red. Homer tried the same method and found the 123-A3 pushed inward. But Homer denies any wrongdoing...
The 2213H’s are in a friend’s hands now. I guess I’ll have to test the strength of our friendship to find out how the 2213H’s sound in the 4311B’s. (It’d been years since I last heard it)
Did you say 'fool'? Homer!
Signed, Homer, uh, Ned, eh, KenMiles.
Last edited by KenMiles; 07-27-2007 at 09:02 PM. Reason: grammar
That's OK - swapping is fun, but can result in unintended consequences... There's some cool freeware to help you model box response, and the T-S parameters are pre-loaded in libraries - helps avoid mishaps...
Impossible.
So, is the replacement transducer the D123? Regardless of you getting inverse results from "your" polarity test on the 2213H, the D123, 123A-3 and 2213H should all test the same (cone in on (+) signal). I'm quite confused...
You should do this, Ken. Too many questions for a simple LF swap...
Only if they have been reconed using the wrong kits.
Again, have Homer send me the 2213Hs, that we might resolve this matter in reasonably short order....
No recone, original 1979 or 1980 cones. My brother owned the 4311B's for most of these years but was SO desperate to own a computer that I was able to trade a computer for my old JBL's. Talk about a ripoff! But it's fair, given the deal he got on them from me.Only if they have been reconed using the wrong kits.
Again, have Homer send me the 2213Hs, that we might resolve this matter in reasonably short order....
Jeepers, Bo, Zilch, JBL-meisters, I'll have Homer confirm the polarity of both drivers. Maybe there's a number Homer didn't take note of, like 2213H-1 or something like that.
Meanwhile, regardless of what the T-S calculations may say, the speakers do sound good, especially the well defined bass. The bass is only there when it's really there, and goes deep, if that makes sense. The only weird thing is the reverse polarity mid-range. I, er, Homer, does believe he's hearing the doughnut hole in the mids, especially when A-B vs. (corrected) Sonab OA-14's.
You know, Zilch, Homer gets lost in that NorCal freeway system - I mean he thinks he's headed to Hayworth and winds up taking a left(ist) turn in Berkeley!
See, your OP indicated the replacement driver has an AlNiCo motor - correct? Then it is certainly not the 123A-3.
Yea, Ken - do confirm the driver number, and it would be good to double-check the cone excursion. (+) to red should give cone in movement.
someone at jbl could have been drunk and inverted the polarity on some mags (hey you never know)
Pelly, what Homer gathers, (and Homer doesn't recall from exactly where) JBL's initial solutions to meet the current polarity standard came in a mixed bag- drivers were changed, some speakers were worked out in the internal wiring, and some speakers were simply cross-wired at the connector posts.
What Homer?
They were drunk?
Okay, I'll get off my box now-
"... and go determine what drivers are actually IN my 4311Bs."
["OH, and how I have them CONNECTED, too...."]
Hi Zilch."... and go determine what drivers are actually IN my 4311Bs."
["OH, and how I have them CONNECTED, too...."
Homer is very reluctant to remove the woofers again. When he originally removed the 2213H's, the seal became an adhesive over the years which tore chips of particles away from the baffle. Homer's removed the woofers twice, which each time removes more chips.
When I have Homer remove them again, it'll be specifically to install gaskets to remedy that problem, and possibly repair the damage to the baffle edges.
The current install for the 123 A-3's is wires 'reversed', with the green wire with the black stripe (positive) connected to the black driver post, the green wire (negative) to to the red driver post.
At the time of the swap (last week), Homer confirmed checked the total system, which the woofer pushes out when positive battery goes to the red post on the back of the cabinet.
The only other evidence Homer can provide is a description of the 123 A-3 drivers. Unlike the 123 A-1's, they have robust rectangular spokes. They're also 8 ohms.
The guy who Homer bought them from said they came out of L100's, which story fits- they're painted semi-gloss black (not grey as their 2213 professional counterpart).
The magnet housing is also distinctly different (smaller diameter) from the original 2213H, but the frame casting spokes are the same as the 2213H.
There's a pair of 2213 woofers currently listed on ebay. See:
http://cgi.ebay.com/JBL-2213-123A-3-...QQcmdZViewItem
There's a pic showing the rear view of the drivers, which is identical to the 123 A-3's except for the color.
Otherwise, can you'll wait until Homer is ready to install gaskets? I'll lend him my camera so he can post pics.
ThanX,
There are currently 1 users browsing this thread. (0 members and 1 guests)
Posting Permissions
Reply With Quote
