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JBL 4311's = system complete... for now.

I would also like to point out that I've never rebuilt a crossover network before either! Hooray newbies!

But, I'm going to attempt it, and if I fail, I'll just take the one I screwed up apart again, and find someone more qualified to put it back together.
 
Okay, Gonzo. I like to start simple. Get my feet wet and take it to the next level. If the 4311 xover is simple than that's where I'll start. It's just that some of the xover pics on the cap replacement sticky were insanely intimidating. The CS99's for example...'birdsnest' comes to mind. The board that brain pictured is more my level. I'm pretty confident I could tackle that job. It was the reverse side of the CS99 board that scared me.
I'll check out the unpooching link tomorrow. Love that word! I'm thinking a bent office staple may do it if done carefully. Will also get the foam surrounds for the tweeters.
I almost bought a broke pair of McIntosh ML-1's. Needed refoaming and an equalizer. Decided to redo my JBL's instead. If the macs are still available this weekend I might grovel. Man, I have no pride sometimes! But I've always wanted a pair since the early 70's.
The St. Pete Gran Prix is this weekend so I may not be home too much.

Thanks, Brain, Gonzo, Zilch. You help keep this site alive for me.

Rick

I had to skip getting the plumber plugs today....had something to do (rearrange my shoe trees and empty the toaster). Actually checked a different Home Depot, and they didn't have them either. All will be accomplished asap, but I keep running into prearranged plans my wife made for me that I didn't know about! It's all good, however.
 
While we're on the subject of 4311's... what effect, if any, would swapping the 2213 woofers for 2213H woofers be? :scratch2:

According to what I've been able to find, the 4311 and 4312 crossovers look relatively identical. The 4311 is rated 50 watts and the 4312 is rated 75 watts. Is this entirely due to the extra power handling capability of the 2213H vs the 2213 or is the midrange beefier too? They both use LE25 tweeters.

Bonus question: Would the impact be the same for the 2213Hs in L-100As?
.
 
2213 is 123A-3 in Pro uniform.

2213H has a ferrite magnet in lieu of alnico.

This upgrade to 4311B (75W) spec facilitates overdriving the cone (pics below) without concomitant driver demagnetization.

To boom your brains out, purchase L200(A), JBL's "Quintessential Rock and Roll" speaker, instead.

[L100 on steroids :thmbsp: ]

http://audioheritage.org/vbulletin/showpost.php?p=5964&postcount=2

http://audioheritage.org/vbulletin/showpost.php?p=12227&postcount=14

http://www.dangerousdecibels.org/hearingloss.cfm
 

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Looks like someone cranked it a lil' too much! Damn, the woofers look like the bobbin jumped out of the gap :nono: . I agree about the Alnico woofers de-magging due to heavy work cycles/time, I wonder if the LE5-2 is affected to the same degree? GT seems to indicate that it takes a pretty big flux to do major de-magging. Efficient Alnico cone midranges might still be okay, dunno. I like the LE5-2 the best, I hope so. So Rick, I hear ya, this is going to be just the right project, nice and simple, with real audible rewards for your time and efforts. Can't be any better than having Zilch guide the technical aspects, you're both extremely lucking. No guess work. Thanks Zilch, I know we've had some differences, but I've always respected your ability and your passion for this stuff. I'm good, hope you are too. Let's get some mods going Gents, I can't wait to read the results, regards, Steve G.

Edit: I just looked at that last link Zilch posted. Holy DB level Batman!! I didn't realize that SPL's that low can and do cause damage. I stood about 5 feet from a massive tower of SR speakers at a Van Halen concert back in '79. I remember the ringing that lasted for what seemed like a week, no kiddin'. I remember shooting a .357 Magnum (about 50 rounds) without earplugs when I was about 30, so.., thats 15 years ago. Man, we gotta watch those levels. I'm going to play my system at my normal max. volume and monitor it with my trusty RS. SPL/DB meter. I must know what I'm really doing to my ears. thanks for that Zilch, I had an idea about over 100db exposure, but no clue about sub 100 db exposure.
 
Zilch said:
2213 is 123A-3 in Pro uniform.

2213H has a ferrite magnet in lieu of alnico.

This upgrade to 4311B (75W) spec facilitates overdriving the cone (pics below) without concomitant driver demagnetization.

To boom your brains out, purchase L200(A), JBL's "Quintessential Rock and Roll" speaker, instead.

[L100 on steroids :thmbsp: ]
Thank you Zilch. I somehow recall JBL touting the 2213H as having an improved voice coil and magnet design with a beveled edge that dissipated heat better? (Think I saw something about it on the Heritage site, which piqued my interest.) That's what prompted my inquiry, as I wasn't sure exactly how they compared to each other. Do you have a preference between the three models?

Also, as a musician, the debate still continues over the sonic desirability between alnico and ferrite magnet speakers. Care to share the view from the professional audio side of the street? Are 123-A/2213 preferred over the 2213H when paired with other components like the LE25-x tweeters and LE5-x mids, or is it just a matter of personal preference and taste?

Thank you for the links too. Think I'll pass on the L-200... :)
 
sleddogman said:
Do you have a preference between the three models?
Throwing in the original 123A-1 (and there may have been a 123A, as well, though I'm not certain I've ever seen one) there's four or five versions actually.

JBL was careful in their designs when switching to ferrite magnets. Frankly, I can't hear a difference. Most any alnico 123A-x or 2213 will be partially demagnetized; they're one of the group of JBL drivers subject to that from driver current, and I wouldn't guess there are many around which haven't been subjected to considerable of that over the years.

However, the deficit is typically small, on the order of less than 5% of original magnetic strength, and remagging them is not worthwhile. The weaker domains will simply demag to the same level once high currents are applied again.

In this respect, then, 2213H is preferrable, but if you play them stupid loud, the cones become the weak link. They will fatigue along the line shown in the pics, and ultimately require reconing....
 
gonzomeep said:
Man, we gotta watch those levels. I'm going to play my system at my normal max. volume and monitor it with my trusty RS. SPL/DB meter. I must know what I'm really doing to my ears.
A-weighted, 30-second integrated average. Report your findings here, please, or start another thread on the subject. Rick and other members could post their results, as well, for comparison, and discuss the applicability of those and other standards.

Seems to me some links to that and similar sites belong up in the "Announcement" box at the top of each page here. Perhaps the Mods and Administrator could discuss doing that. We're talking real "Equipment damage" here.... :yes:
 
Ok folks, got of the phone with JBL, not surprisingly, they don't carry parts for much of the 4311's or the 3112 crossover networks. What they do have is Part Number 53363 that's the foam disc that's supposed to be around the LE25-2 Tweeter. $2.04 compared to ~$10 on some super famous auction site.

Number is 818-894-8850
Hours are from 8-5 PST Mon-Fri, and best hours to call are from 8-12 and 2-5 PST.

Still trying to find proper L-pads. Will post later.
 
Brainwashed said:
Still trying to find proper L-pads. Will post later.
Parts Express L-Pad will work fine. I believe the 50 Watt ones just fit, though there may be shaft length issues to resolve....
 
They have 3/8" shaft, and 1" shaft variations of the 50 Watt versions. I'm taking some measurements to see if the 1" version is suitable.

EDIT:Yep 1"

EDIT:

Parts Express 50 watt 1" shaft L-Pads DO NOT FIT they are too wide by about 1/8" on each side.
 
Just make sure that they will also sit side by side. The 50 and 100watt versions may have a greater circumference. Not the shafts, but the actual bodies. Those pots sit really close to each other :scratch2:
 
Tapehead47 said:
Maybe someone more qualified should do the recapping for me is what I'm thinking...

Rick

Hey Rick, I'm no tech by ANY* standard, but I can handle a job like that. We're a half hour apart if you run into problems!

*Unless an ex auto tech with some electronic training counts!
 
gonzomeep said:
Just make sure that they will also sit side by side. The 50 and 100watt versions may have a greater circumference. Not the shafts, but the actual bodies. Those pots sit really close to each other :scratch2:

Too late. They don't. :tears:

So, I still need to find some L-Pads that fit side by side at 1 3/4" center to center.

The Parts Express versions side by side sit 2" center to center.

Crap.
 
50W = 1.965" square
15W = 1.605" round

One of each = 1.785" c/c.

Maybe fit, it's 0.035" interference.

If so, use 15W on the tweeter.

Same drill at Madisound, looks like....
 
So, after a bit of further investigation, I have come to the realization that no Parts Express 50 watt L-pad is going to work properly. Even sitting on the bottom of the cab, by itself, the 50watt L-pads are still too tall to fit in the center of the knob hole. They do 'fit' however, and provided I can modify the network board with a piece of luan board or some such, it should be minimally invasive, and although not original looking, i think I can make it function like it's supposed to.

Parts-Express L-Pads sitting on the bottom of the Cabinet:

 
Do as Zilch suggests and buy a 15w pot for the tweeter. That will work from what I see. This a common practice. JBL does did it commonly. I do not recommend changing the cosmetics of your speakers when it can be avoided, especially when another good alternative is available. Hang in there, you're just about ready to go :thmbsp:
 
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