JBL 4343 rebuild and configuration project

[Fangio]

This thread is dedicated to the respectful rebuild and configuration of two JBL 4343 Four-Way Studio Monitors from the scratch, in different evolution steps. Their startup could be just as subwoofer cabs, they will become 2-ways by adding horns and crossovers, and so on – 3-ways by adding UHF drivers, and end up as 4-ways again, once the rare midranges pop up. The steps may vary from this roadmap, depending on the components that come across my way. A way to go from the start, or a follow-up action could be even to improve them very carefully to 4344s using original components within the JBL specifications, like some others have done it before. Due to the rarity of these monitors and the increasing value of their components on the market (which makes them harder affordable within a reasonable budget), this attempt is declared as longtime project. The goal is to get to know all aspects of a full restoration project, with existing 4-way cabinets as basis that leave all options open.

Please don't expect news every day, week or month. Searching before asking, and try not to ask all questions again that have been discussed at this forum before is obligatory from my side. Comments on all aspects, questions, technological help or hints to find missing parts are most welcome.

[Fangio]

I bought this pair of empty cabinets on ebay in january 2006, for 170€. This is what i have, and its not much:

- utility cabinets in light grey, obviously.
Condition is ok over all, and they have black (and removable) baffles. I have to admit that i prefer that (blue is definitive not my favorite color ) They would benefit from some walnut re-veneering though, a job that could be done any time. My advantage is that i would not need to refurbish old veneer, and could apply a grain of my choice. (A great example is what Rolf did here: http://audioheritage.org/vbulletin/s...ead.php?t=8777)

- grilles in black, fortunately.
They are almost perfect, no holes tears etc, not faded, plain black. Looking at them from the inner side, they are built impressively complex, and worth the money alone. No call for action, except to find some badges again (hard enough).

- 2308 lenses.
No call for action.

- all screws for the woofers, and midranges.

What i don't have: original 2121, 2231, 2307, 2405, 2420 drivers, 3143 crossovers. And i know these are not to find over night.

[Fangio]

I had several pair of these duplicated from my originals. I had them made without serial #'s. Anyone interested can pm me.

Hey Dave, thank you for your offer. Your foilcals look fantastic. I've read a bit about their reproduction in these threads:
http://audioheritage.csdco.com/vbul...read.php?t=2373
http://audioheritage.org/vbulletin/s...?t=4543&page=2

You'll get a pm.
Something to my background, i'm a prepress pro, since the 80s. Although its easy to ask others if they have some foilcals left: printing in ANY way is something that i'm more skilled in, and it will be a nice challenge to see if i can't do that too, with the ole G4 at home and some Adobe stuff.

The good news is that you can make these "upgraded" 4343s by putting in 2235H woofers, 2122H mids, 2421 compression drivers and 2405 slots. With building or slightly modifying a 3143 crossover, you'll have some "killer" studio monitors. You should consider bi-amping these.

Keep us posted!

Tom

Tom, thanks a lot, i know. When i see the market for the original 4343 alnico assembly, i feel they are a bit overpriced nowadays. So this is a main decision before i start hunting drivers, and i'm still going through the pros and contras in older threads. I guess it could turn out like you suggest, but additional opinions are welcome. In fact, these cabs used to be 4343B's until last year, so they were loaded with xxxxH (ferrit) drivers before, right?

Congratulations on your nice find and welcome to my addiction. An original 3143 crossover would probably be the hardest thing to find. But if you're interested in upgrading the drivers to 4344 spec, as suggested by Tom Loizeaux above, you'll want to make yourself some upgraded crossovers also. Much has been written about this in the ongoing "4343 to 4344 Upgrade" thread.

porschedpm, thanks too. Great, so many owners/experts here I regret that i didn't bid consequently on the original 3143 crossovers from the same guy, to be honest, i thought 120€ could be enough. They ended at 204, though. Next time i'm better prepared, they are indeed extremely rare. Is that a common value in the US, too? I will consider having them rebuild also, know a collector in Bremen who offered me that.. probably more have done that here too.

[frank23]

good luck rebuilding the 4343's. It is still very sad [especially for Fangio] that these speakers of which Fangio bought the cabinets were still complete in december 2005 in Ebay auction 7568749119 and that the buyer butchered them, leaving the parts to be rebuilt by those who care, but only with lots and lots of effort. Such a waste!

below a picture of the actual speaker of which the cabinets are now owned by Fangio. They sold for 1.310 euro...

Fangio, why don't you send the buyer of the crossovers from this speaker a message asking them for how much he'd sell them back to you? He bought them for 204 euro in auction 7577458631 on ebay.

[Rolf]

With regards to the people that originally built the 4343 you are in your full right to use whatever components you choose. Have I got your post questions wrong?

You say that you perfer the black baffles, and I uderstand you mean the front grills. That's good.

The thread you refer to, about my kind of way to veneer the speakers I can highly recommend. If you want any more info, pm me.

As Tom stated, the 2235H is a great improvment. The differnce from the 2121H (in my 4343's) to the 2122H, as Tom reccommend, I am not sure. Ask them who has heard both the difference. Same goes with difference from 2420 to 2421. The 2405 is the same, and with improovment of the network things should "Rock ". Of corce you MUST be-amp. That is what really makes things sound better.

If I understand you right, you do not have a nerwork. Ask Guido to make some for you. Soon I will do the same.

At the end I say that I am not a very "tecknical guy", just use my ears and locical know-how. Hope my answer help you.

Rolf

[Fangio]

With regards to the people that originally built the 4343 you are in your full right to use whatever components you choose. Have I got your post questions wrong?

No.
As you and Tom said some drivers are generally regarded as an improvement, i.e 2235Hs to 2231Hs. OTOH the difference from 2121H to 2122H seems to be more controversial.

You say that you perfer the black baffles, and I uderstand you mean the front grills.

I meant the utility cabs have both in black. Combined with walnut that would (will) make a perfect combination to me.

The thread you refer to, about my kind of way to veneer the speakers I can highly recommend. If you want any more info, pm me.

Thanks. I'm looking around for a source of the kits described in this thread.

If I understand you right, you do not have a nerwork. Ask Guido to make some for you. Soon I will do the same.

At the end I say that I am not a very "tecknical guy", just use my ears and locical know-how. Hope my answer help you.

Rolf

Yes it did. To get the woofers and networks has priority 1.

Just to make that clear i'm not in a hurry at all. My intention for near future is to use the cabs as experimental playground, for mounting and checking out several drivers that may come along. Hearing them as 4343s again is kind of a long-term objective.

[Rolf]

I will follow your posting as the progress moves on. Good luck!


Rolf

[4313B]

OTOH the difference from 2121H to 2122H seems to be more controversial.

There is nothing controversial about it. We've discussed this before. The 2122H is definitely superior to the 2121H. The 2121H had breakup issues that were fixed with the 2122H. The 2123H is the best of the bunch but it isn't a bolt-in in a 4343 or 4344/4345 and it doesn't go as low as the 2122H due to it's more powerful motor. The biggest issue with the 2122H might be it's short coil which could be a problem in high power applications where a suitable high pass filter isn't used. I've personally never had a problem with it because I've never driven it that hard. With the stock 4344/4345 network it isn't an issue at all.

Think about it for a nanosecond or two... would G.T. have bothered with the 2122H in the 4345 if the 2121H was all that? I don't THINK so!

If you have 4343's and you like them as is then you're done and you can sit back and enjoy them. If you have 4343's and you want to try the 4344 components and networks you have that option and it's a nice option to have. It's no different in concept than an L250 to 250Ti upgrade. Some people like the L250 as is and will never upgrade and that's fine.

Has anyone bothered trying the 4344 MK II upgrade?

Note that the 4345 used the 2421B in early production runs.

[Ian Mackenzie]

I key issue for you at this stage will be to either do a complete restoration to 4343B spec or opt for the 4344 spec. Only you can make that decision.

The 4344 is a better loudspeaker and if you take that course there are a number of embelishments to consider depending on your budget and how far you want to go.The 4343B also has a certain historical significance.

Regards either a number of us have been there and done that and hence its not the not quite the kind pioneering exercise as might be suggested.

I am sure you will enjoy the journey and as you say take your time. The anatomy of this system certainly takes some appreciation for a first timer.

Ian

[Uncle Paul]

Has anyone bothered trying the 4344 MK II upgrade?

Has anybody in the Forum listened to the MK II? I wonder how it would compare to the previous generation? I've read where it was supposedly voiced for Japaneese music.

[Ian Mackenzie]

Someone is Australia has a pair and posted sometime ago about the sound. He changed out the woofers and put in 2235H's.

I imagine the dusted diaphragms are nice.

As I recall it was bass shy. Surprise surprise. Easily fixed with a bit a low end boost. If I had my time again I would recone the 2231's as 2234 and boost the low end or stack a second 2234 for quassi 4445-

[Fangio]

I key issue for you at this stage will be to either do a complete restoration to 4343B spec or opt for the 4344 spec. Only you can make that decision.

The 4344 is a better loudspeaker and if you take that course there are a number of embelishments to consider depending on your budget and how far you want to go.The 4343B also has a certain historical significance.
...
Ian

Now we are talking.
Yeah this decision has to be made: straight restoration back to classic 4343Bs again? Or wolfs in sheep's clothing: old classic cabinets and baffles with upgraded, better content, kinda hotrodding within JBL specs. I do tend to the second choice, and to say it with Frodo's words: „...but i don't know the exact way...“

Some thoughts: the newer drivers maybe show up more often on 3-2-1. And as i learned from local PA pros too, many drivers could be reconed to the newer specs, i.e.: 2215, 2231H, (even E140s) could be reconed as 2235Hs. That exceeds the field to search. Even E110s could be reconed as 2123s(?), i'm watching a pair right now. OTOH, the list of arguments to stay within the 4343 specs is short: originality, or are there more? JBL had their reasons to improve these speakers.

I hoped very much when buying these, the owners of the classic four-way JBLs at LH could be attracted by a thread like this, to share their immense knowledge and let more old bad boys growing to new glance, than their own, ready ones. This could be fun also, huh? Sure, obviously i would benefit a bit.. just correct me where i go wrong. Giskard, Ian, your help is much appreciated.

Giskard, now i have to learn about 4344/4344 MKII and 4345 as well. And in opposite to most of you, i haven't heard them all. Promised, a bit of this weekend is dedicated to the upgrade thread, that porschedpm suggested.
F.

[Earl K]

Some thoughts: the newer drivers maybe show up more often on 3-2-1. And as i learned from local PA pros too, many drivers could be reconed to the newer specs, i.e.: 2215, 2231H, (even E140s) could be reconed as 2235Hs. That exceeds the field to search. Even E110s could be reconed as 2123s(?), i'm watching a pair right now. OTOH, the list of arguments to stay within the 4343 specs is short: originality, or are there more? JBL had their reasons to improve these speakers.

- A lot of your assumptions on reconing ( posted in the above quote ) are incorrect .

- One must match the top-plate depth ( gap depth ) , as well as match the original magnet strength ( gauss level in the gap ) to expect to recreate the original transducer specs . The magnetic assemblies of the 2225H / 2205H / 2205a, are good candidates to turn into a 2235H woofer .

- Use the sites' search engine to find out all the woofers which will accept the 2235H recone kit . ( off the top of my head I don't have a thread to steer you towards / but there are many in the archives )

[Fangio]

Oops.
You are right Earl, of course.
Won't refer to that kind of sources, or post unverified stuff again. Its all here, found the appropriate threads. 2235Hs are certain now, I've heard the king of the the 15" some times, and the recone kits are not that pricy.

For now its seems the best to stay close to the chart from Giskard, and consider Toms short upgrade path – it has the most advantages. Also I understand that this is not just vintage JBL but also the pro series, and so another league. No prob to admit that, and hope there is no barrier. What i want is as best as possible sounding highend loudspeakers, if they also meet the requirements for museum pieces thats nice but comes in second place.

if you take that course there are a number of embelishments to consider depending on your budget and how far you want to go.

If you're talking about fundamental considerations, i would be pleased if you could elaborate this, Ian. Thanks

[Robh3606]

Hello Fangio

I scratch built a pair of 4344's using plans I modifed from the 4345 thread and networks that Ian built using Giskards first network solution for the missing taped inductors. It was a fun project. They were well worth the time and money put into them. Looking over the threads will be a big help to you. If you don't already have some you may want to consider getting a basic measurement set-up. Could be as simple as an SPL meter or an inexpensive 1/3 octave RTA. Once you get things going having some kind of measurement capabillity will be invaluable as you balance the driver levels, verify phase as examples. I know it made a big difference for me. Good luck on your project. Please keep the pictures comming. Attached is the matrix for the cone kits. Watch the note on the E130/140

Rob