PDA

View Full Version : ;y little naive friend and 4341 drivers



marijan
04-18-2008, 10:55 AM
Hello. Sory guys, but i didn`t menage to find an ansver browsing the forum. I do not know much about this things.

Friend of mine traded his Usher speakers for a set of new Harbert`s 5 and so called set of drivers for 4343 or 4341 monitors. Since a kind of wood work is my job, I was picked up to make him a cabinets.
After he showed me a drivers and after my lurking around the net about JBL`s I realised that he did not get what he thought he will get. 2405 are OK, 2420 with horns allso, 2231 does look as 2231 with alnico magnet assembly but on the membranes there is a 2235H sigh writen with chalk (woofers where reconed). Main problem is 2121 which is not 2121 but LE10A. Can he use it in either 4343 or 4341 project or is it waste of time? He is woried that LE10A will be inferior to originals soundvise. 2121 will be hard to get as I can see...

Thank you for any opinion or suggestions.

Marijan

louped garouv
04-18-2008, 11:20 AM
http://www.audioheritage.org/vbulletin/showpost.php?p=16998&postcount=5


You can recone LE10A's as 2121's if need be. Be aware that the latest C8R2121 recone kits from JBL have the wrong center dome in them and won't lay properly. You'll need to find some old LE10A or PR10 domes and use them.

maybe this can help...

:)

hjames
04-18-2008, 12:36 PM
Information and pictures on the various 10 inch drivers
http://audioheritage.org/vbulletin/showthread.php?t=16962&

Information on the 4341s
http://audioheritage.org/vbulletin/showthread.php?t=16493

Tech references on the 4343s
http://audioheritage.org/vbulletin/showthread.php?t=16951


Hello. Sory guys, but i didn`t menage to find an ansver browsing the forum. I do not know much about this things.

Friend of mine traded his Usher speakers for a set of new Harbert`s 5 and so called set of drivers for 4343 or 4341 monitors. Since a kind of wood work is my job, I was picked up to make him a cabinets.
After he showed me a drivers and after my lurking around the net about JBL`s I realised that he did not get what he thought he will get. 2405 are OK, 2420 with horns also, 2231 does look as 2231 with alnico magnet assembly but on the membranes there is a 2235H sigh written with chalk (woofers were reconed). Main problem is 2121 which is not 2121 but LE10A. Can he use it in either 4343 or 4341 project or is it waste of time? He is woried that LE10A will be inferior to originals soundwise. 2121 will be hard to get as I can see...

Thank you for any opinion or suggestions.

Marijan

Mr. Widget
04-18-2008, 01:16 PM
2231 does look as 2231 with alnico magnet assembly but on the membranes there is a 2235H sigh writen with chalk (woofers where reconed). Main problem is 2121 which is not 2121 but LE10A.As you surmised, the 2231s are likely fine... assuming they were done properly.

As has been pointed out, the LE10As can be reconed as 2121As (I don't believe that actually ever existed, but they should be fine.) If you do not recone the LE10As, they can work, but you would need to rework the networks. I would go for the recone.


Widget

marijan
04-18-2008, 01:50 PM
Thank you for clarifications, sugestions and links.

Very supportive forum. What a beatifull pictures of those blue front 4341`s. It makes me wish to get an old, restoration needed par of one of those JBL` and bring them to life...!

I`m from Slovenia. Can some of the European members recommand a good jbl service workshop, for reconing that le10a`s somewhere in neighbourhod (Austria, Germany, .....).

Few days ago, the 3141 network was sold on the ebay for 266$. Is it hard to find this stuf these days or is it likely that he`ll be forced to use a shematic and made the crossovers? If someone is offering those X-O`s send a PM please.

Marijan

louped garouv
04-18-2008, 01:55 PM
probably want to build the networks from scratch...

:)


and look up member Guido for help, i believe he is an authorized center in Germany...

http://www.audioheritage.org/vbulletin/member.php?u=117

hjames
04-18-2008, 02:12 PM
The 4341 Monitor uses the same drivers as the 4343 monitor that replaced it. The 4343 has a slightly larger cabinet. If you have no cabinet anyway, you might decide to just built a 4343 cabinet. You can do a search here to find threads with dimensions and specifics for cabinet construction.

The 4343 monitor can be upgraded to use the newer-design 3145 network from the Model 4345 - http://www.jblproservice.com/pdf/Net...%20Network.pdf (http://www.jblproservice.com/pdf/Network%20Schematics/3145%20Network.pdf)

If you have access to more technical folks, one of the improvements to the big 4-way JBL monitors is to build a "charge-Coupled" crossover network. If you don't have the original networks in the first place, it is a real good way to proceed. A schematic and some tips can be found at http://audioheritage.org/vbulletin/showthread.php?t=16967





Thank you for clarifications, sugestions and links.

Very supportive forum. What a beautiful pictures of those blue front 4341`s. It makes me wish to get an old, restoration needed pair of one of those JBL's and bring them to life...!

I`m from Slovenia. Can some of the European members recommend a good jbl service workshop, for reconing that le10a`s somewhere in neighbourhood (Austria, Germany, .....).

Few days ago, the 3141 network was sold on the ebay for 266$. Is it hard to find this stuff these days or is it likely that he'll be forced to use a schematic and make the crossovers? If someone is offering those X-O`s send a PM please.

Marijan

Fangio
04-18-2008, 02:27 PM
Welcome to the forums.


..3141 networks ... Is it hard to find this stuf these days or is it likely that he`ll be forced to use a shematic and made the crossovers? If someone is offering those X-O`s send a PM please.
Separately offered, the originals are a rare find indeed, particularly in europe.

And yes some members do build improved versions with charge-coupled technology.


It makes me wish to get an old, restoration needed par of one of those JBL` and bring them to life...!

www.violineradaljac.com (http://www.violineradaljac.com/)
You're into building violins??

Thats a good start, and nice background to have, for speaker DIY/restoration. :)

subwoof
04-18-2008, 06:01 PM
The Vb ( LF ) for the 4341 and 4343 are the same. It's been posted many times that they are different BUT if you look at the measurements the 4343 was built taller ( but not as deep ) to allow for the rotatable MF/HF assembly. The volume that the 2231(H) woofer sees is the same.

The 2121 was the alnico version - the 2121H was the ferrite. They used the *same* cone - just as the 2231A - 2231H did on the 15". Look on heathers 4341 ref thread for the picture of the baskets I sent. I also posted side by side pix of the voice coils somewhere...

Note that the "A" designation was NOT used on the alnico raw speaker frames that were *not* included in the component section of the JBL catalogs. A minor but repeatable quirk on JBL's part. They did however use the "H" on ferrite components that were in later monitors / consumer ( IE: 108 in the 4315 and 108H in the L250 - neither were listed in catalogs )

When the 2231H was repainted black, it got a new coil + glue and became the 2235H. They are VERY close in performance and if needed to be replaced, should be done in pairs.

If you have a hardcore need for a 2231 cone assy I think I have a good one pulled from a basket in storage BUT with ANY LF foam surround cone, I recommend a NEW recone for correct performance....:)

sub

readswift
04-18-2008, 08:23 PM
hahaha funny topic . I want to get my share of this type of stumble-upon-naivity too ...! :applaud:
Seriously, I'll pm you (I need veener , no crossover talk this time :D ) .

marijan
04-19-2008, 12:00 AM
If you wana talk flamed or birds eye maple vilon makers veener readswift, you are on dangerues and expensive teritory. PM me please on my private mail , you can found on the contact page of my website please. I have a dificulty to figure out how to read a private message on the board:blink:. I can se only your name and a red green tape there. What button do I have to push.

Hjames, thanks for the links. A friend does have a guy who would be able to make those 3141`s, but he`d like to have original pots suroundings, hi quality material in it etc. Even I made few tube amps in the past, so we shoud be able to do the job. Anyway if someone is willing to sold a pair, he is prepared to go up to the 300 EUR limit for a set.

Subwoofer, I can not find a heaters 4341 ref thread. I`ll take few shots of those LF`s.

I`ll contact Guido, for reconing.

When I got my PMC IB1 monitors, I said that these are the last speakers I bought for the rest of my life. I need to hear some of these beautis of yours. It may force me tho change my mind...

Thanks for beeing so helpfull.

Marijan

richluvsound
04-19-2008, 03:12 AM
I`ll contact Guido, for reconing.

When I got my PMC IB1 monitors, I said that these are the last speakers I bought for the rest of my life. I need to hear some of these beautis of yours. It may force me tho change my mind...

Thanks for beeing so helpfull.

Marijan


Guido,

is a one-stop-shop ! He can probably get you a schematic for the CC crossovers.

BTW. the larger PMC pro range are a fine sounding box. The domestic range however- utter crap in a cute little jewelry box !!!!!!! even with a Bryston powering them. You will certainly notice more warmth from the JBL's . TBH, PMC are over rated IMHO. Genelec do that kind of sound better.
PMC are Bleached of all the romance.

Ps I have heard the IB1 S and most of the domestic range. The VOLT 10" is a very good driver from what Iv'e heard. Mind you, fillet steak is only as good as the chef !

4313B
04-19-2008, 03:20 AM
( IE: 108 in the 4315 and 108H in the L250 - neither were listed in catalogs )Just to clarify, the 4315 used the 2108 (AlNiCo) or 2108H (SFG ferrite) which was the pro version of the consumer 112A (AlNiCo) or 112H (SFG ferrite) (L212). The L250 and 250Ti used the 108H which was the consumer version of the pro 2118H.

When the 2231H was repainted black, it got a new coil + glue and became the 2235H. They are VERY close in performance and if needed to be replaced, should be done in pairs.http://audioheritage.org/vbulletin/showpost.php?p=46738

Mark Gander did the 136/2231 and Greg Timbers did the 2235. The 136/2231 was a severely overdamped design with very high compliance as was its 12-inch sibling the 124/2203 (extremely powerful motors, loose suspensions). These older drivers were completely dominated by the enclosures they were typically used in (reference their Vas values).

marijan
04-19-2008, 03:29 AM
Here is a couple of JBL drivers shots my friend have. I hope this will work!

BTW PMC IB1 is a pro range studio monitor. In my turntable based sistem, I do not feel any leek of romance.

4313B
04-19-2008, 03:59 AM
Well, the LE10A is a very smooth performer but it won't have the same impact as the 2121 or 2122. Also, that aquaplas coating on the LE10A kills efficiency (it increases bandwidth and decreases sensitivity in addition to damping spurious resonances). It may be that someone wanted to cross the 10-inch 3-way over much lower and so they used the LE10A (not necessarily a bad thing, some people like having one driver handle the entire fundamental human vocal range).

The 2121 and 2122 recone kits are still available so you might just want to recone those LE10A's as 2121's or 2122's.

marijan
04-19-2008, 04:09 AM
Well, the LE10A is a very smooth performer but it won't have the same impact as the 2121 or 2122. That aquaplas coating kills efficiency. The 2121 and 2122 recone kits are still available so you might just want to recone those LE10A's as 2121's or 2122's.

Yes, that was recomanded on the start of the thread. I sent a PM to Guido, and in the same time I`m looking for a recone kits. Where the h... can I found a pair if Guido does not have it? You say that those are avaliable. Can you point me in wright direction, please.

Someone mentioned that on the newer kits the dome will not fit and that the old le10a domes can be used. If a friend have a pair of le10a that will be reconed, those domes can be used when reconing to 2121, correct:blink:?

Marijan

4313B
04-19-2008, 04:17 AM
Where the h... can I found a pair if Guido does not have it?Guido can get them.
Someone mentioned that on the newer kits the dome will not fit and that the old le10a domes can be used. If a friend have a pair of le10a that will be reconed, those domes can be used when reconing to 2121, correct:blink:?I'll try to check the latest kits this weekend and see how the domes are fitting these days. And yes, the LE10A domes were the same as the 2121 domes (at one time).

marijan
04-19-2008, 05:12 AM
Guido can get them.I'll try to check the latest kits this weekend and see how the domes are fitting these days. And yes, the LE10A domes were the same as the 2121 domes (at one time).

I hope that Guido will answer positivly. So, if I do understand you corectly 4313 if he get a 2121 or 2122 kit, and send LE10A to Guido for example, Guido will not have a problem to make out farly god 2121/2122 drivers out of those LE`s? (dont take me to hard for my (un)undestanding and bad use of your language)

Thanks for readynes to check out those fittings!

Marijan

P.S.
What about the photos of 2231 LF`s I sent. Do those look OK. Like I said the baskets are suppoused to be 2231 Alnico but reconed with 2235H (at least that is the number writen on the back of the membrane with a chalk).

hjames
04-19-2008, 05:32 AM
Marijan

P.S.
What about the photos of 2231 LF`s I sent. Do those look OK. Like I said the baskets are suppoused to be 2231 Alnico but reconed with 2235H (at least that is the number writen on the back of the membrane with a chalk).

Thats what I have in my 4341s downstairs. I found them (used) with 2234s but I got a pair of 2231s reconed to 2235s from a forum member last summer.

Here are 2 threads on the 4341s:
The 4340/4341 Technical reference thread -
http://audioheritage.org/vbulletin/showthread.php?t=16493

Thread about the pair that I found
http://audioheritage.org/vbulletin/showthread.php?t=16263&page=10

Fangio
04-19-2008, 05:53 AM
2231 cone kits are no longer available, but 2235H kits still are, Marijan.

These are the only proper way to recone 2231 A or H's nowadays, recommended by JBL.

So what you have are 2235's with original alnico motors. Nice, and certainly adequate for your 4341 project – don't worry.

marijan
04-19-2008, 06:06 AM
hjames, yes that one on the left is the right one. Thanks.

I will not bother you anymore guys (at least not all the time), and will do some moore search on my own. It`s just... so much to read, that I`lm begining to regret that I said yes to a friend of mine;). I don`t like to do work negligent, flimsy and just on half. What about my violin buisnis?

Thanks again.

Marijan

subwoof
04-19-2008, 11:35 AM
It looks like the "rusty" 15" is a later version "K" magnet ( note the recess on the magnet casting ) and has an "E" frame ( note the terminal flange ). This will still result in the correct alignment but it makes me wonder if there are any other shortcuts in it's construction..??

4313: I didn't know all of the older alnico consumer equivalents so thanks for the 108 info. I have a pair of 4315 cabs that need those 8's if I decide to return them to original..:o)

sub

ps the link I was referring to is Hjames / *heathers* ( please check your spelling )

readswift
04-19-2008, 04:06 PM
"2231 cone kits are no longer available, but 2235H kits still are, Marijan."

I hope this "still" is not synonymous with "yet" :applaud:

marijan
04-20-2008, 02:46 AM
It looks like the "rusty" 15" is a later version "K" magnet ( note the recess on the magnet casting ) and has an "E" frame ( note the terminal flange ). This will still result in the correct alignment but it makes me wonder if there are any other shortcuts in it's construction..??

sub

ps the link I was referring to is Hjames / *heathers* ( please check your spelling )

Sub, if I did my quick homework corectly, and if that 2231 has K magnet, it could be only from K130 or K 140. 145 would be to havy, with magnet structure weight at 9,0 kg. Asuming that recone was done properly the woice cole even if it was aluminium one from 130 was replaced with coper one when reconing with 2235H kit. All other data from 130 and 140 relating to magnet, not membrane and voice coile structure, are the same with exception of alnico magnet structure weight (5,9 in 2231 and 5,4 kg in K`s) I could onl see the K driver structure on "heretage" pages, but I supouse that there can not be much diference when membr./V.Coil, basket structures are excluded. What would be the downsides of K magnet in that basket if 2235 recone was done? What other structural shortcuts coud be there?

Anyhowe, I cant do much here about it. Drivers was tested for functionality in temporary cabinets with x-o, that was not for sale unfortunately, and the drivers did performe their work. How corect or how good, I don`t know i did not hear it. When i finish the cabinets, I`ll know better I hope. Still, if any of the members know about 3141 x-o to buy, PM info will be most appreshiated. Still waiting for Guido but 2121 or 2122 recone original kits info would be welcome allso for reserve case.

One more question. Plywood was used for cabinets as I can see. MDF, plywood, hardwood... what is generaly the prefered choice in terms of structural and frequency response functionality ... sonic benefits? The cabinets will be veenered.

Thanks!

Marijan

Readswift, thanks for mail, but the tubeguru frum hungary can not help me, he has onl 4331 x-o.

richluvsound
04-20-2008, 04:24 AM
this topic has been covered in depth - use the search function.

Widget has some interesting ideas. I have had some very good results following his suggestions.
I have been working on some boxes using resin , slate powder,mdf and ply.

The front and back are 18mm mdf internal and 18mm birch ply external with a resin and slate powder 4mm mix between. The bracing is sapele . the sides top and bottom are 25mm mdf . They sound wonderful when I stick my head inside and whistle.

Anyway, I think you are probably the best qualified in the acoustic qualities of timber. I hope you stick around and share some of your unique knowledge on the subject.


Rich

subwoof
04-20-2008, 06:59 AM
It could be a K120, 130 or 140 as all of them had the same magnet. The early K's used the SAME magnet and casting as the 136A so there is no problem.

Later in the K evolution JBL made a newer magnet casting that allowed the rear decal to be recessed ( they get scratched very easy ) when the improved surrounds came out.

JBL kept the original magnets for the home stuff since they were always mounted inside cabinets and wouldn't get scratched right??? :)

When the "E" series magnets came out the magnet's diameter was too large to fit into the recess that the alnico did so a new frame was designed but the top plate-to-rim depth was the same.

Even later "E" and pro speakers had the plastic push terminals that replaced the ( superior ) individual push terminals. A step backwards.

Sometimes in the shop we would put together a "frankenstein" speaker for a guitar rig, drum monitor or such when one was needed right away...

sub

marijan
04-20-2008, 07:17 AM
this topic has been covered in depth - use the search function.

Widget has some interesting ideas. I have had some very good results following his suggestions.
I have been working on some boxes using resin , slate powder,mdf and ply.

The front and back are 18mm mdf internal and 18mm birch ply external with a resin and slate powder 4mm mix between. The bracing is sapele . the sides top and bottom are 25mm mdf . They sound wonderful when I stick my head inside and whistle.

Anyway, I think you are probably the best qualified in the acoustic qualities of timber. I hope you stick around and share some of your unique knowledge on the subject.


Rich

I`m not sure that the goal from thos two, violin and speaker box is the same. In violins you try to make highly acustical and resonant enclosure and in combination with all influential factors (post, arching, varnish...) linear response from a completed product. The violin box works as a driver in your JBL, generating sound waves.
Speaker disigners usualy try to remoove the influence of the box which could, in combination with driver generated frequences, produce unwanted freq. crossings, resonances and responses, destroying natural balance of a driver, enclosure, X-o structure.

In string instruments, you can control in certain way, some of the freq. ranges with careful use of varnish/ground combination. Extension of high freq. range in particulary is something that is quite easely achived for example, but linearity is something that will need some more work than just use apropriate finish.

Adition of frequency ranges created with speaker cabinet, will add some kind of coloration to natural output of the driver, and that may be wanted or may be not. As allways, it is all a matter of sinergy betwen design, materias used, drivers and X-O parameters, and finaly, unfortunatly to many times it will be a mater of subjective valuation.

About cabinet materials, a I did some reading, and I did form an opinion, but as allways it is nice to get some confirmation, that is generaly accepted as the most confident and reliable one:).

Marijan

Subwoofer, thans for clarification. Bad homework I see. I`ll let an owner to dewal with it. I hope that there will not be to many downs becouse of that driver. On the other hand that frankenstein monster was wild but sensytive creature...

subwoof
04-20-2008, 04:49 PM
The woofer(s) will work just fine. It's nice that JBL did keep many of the designs based on a "standard" gap depth to allow interchangeability.

The reason we gave it some scrutiny is to make sure that it is compatible - many are sold on ebay with the wrong kits installed and require reconing ( if possible ) at extra expense.

My L200's that are in the living room have the exact same cones and frames as yours and work just fine.

As far as the enclosure, there are numerous threads on that subject that will help you decide. It is correct that the cabinet should be as rigid and non-resonant as possible so 6" of concrete or 1" of lead should work well..:)

Most builders use particle board since it doesn't have grain, is very inexpensive and is easy to find. The cabinets I build for clubs, SR companies and other portable use have a myriad of requirements so they have to be high quality plywood.

good luck and when you get these done, sit back and enjoy them before they leave...

sub

marijan
04-27-2008, 01:25 PM
Intermediate question.

I borowed a photo from the forum... thanks!

Can any of 4341 4343 ovners mesure the angle, that front edge of the sides is taking when coming towards the iner (front side) edge of the sides (contact betwen color blue and veener). It looks to me that that angle is stoped before reaching actual edge. How mush of narov part there is on the front look of the edge....:blink:... I hope it makes at least some sense.

Se the photo please. I marked the edge with light red line.

Thank you!

marijan

subwoof
04-27-2008, 06:09 PM
look here:

http://www.audioheritage.org/vbulletin/showthread.php?t=11856

marijan
05-29-2008, 10:23 AM
A little update of progress. Waiting for 2121 recone kits, need pot badges, but it works perfectly. We found some gray version of 4341. Friend wanted blue ones. Only change in original design is an inch higher stand. Friend is a toll huge guy.

Thanks for help everybody. If someone know where to found pot badges, please let me know.

Few shots. I hope you will enjoj. I did. Anyway, it took me three weeks to restore that pair.

Marijan

marijan
05-29-2008, 10:26 AM
here

mech986
05-29-2008, 10:34 AM
Very Nice restoration work!!! You have rescued a very nice pair of speakers and made them look, dare I say, even better than new.

Congratulations!!!

Bart

mech986
05-29-2008, 10:35 AM
Time though to go hunting for the 2308 lenses and maybe have some reproduction labels/L-pad labels made.

Good luck!

Bart

macaroonie
05-29-2008, 10:41 AM
Nice nice work. I hope they sound as good as they look. :applaud::applaud:
Only one fault but you perhaps did not know but exalted draper and member of the forum, Zilch, has original dark blue grille cloth for sale at very reasonable price. He is in California but will post worldwide. Hope that helps.

marijan
05-29-2008, 11:56 PM
Thanks mech986 and macaroonie for kind words.

Sound. Natural, dinamic, balanced with no need to listen loud. Bas response is unbeliveable accurate to 32Hz, after that there is a quite clean cut.
Easy to distinct diferences in various recording approaches. I do enjoy... till sunday. Than, they are gone.

I`ll try to found that cloth you are talking about, and see is it a problem to make lensses.

Marijan

macaroonie
05-30-2008, 01:47 AM
Now you know what to do, you can build your own. :D

marijan
06-02-2008, 10:24 AM
That blody blue thinghs are addictive. I decided to make a pair of 4341 for myself,.... cabinets, networks, lensess... Looking for drivers (at Guido and some other sources)

Nothing realy wrong with my PMC`s, but that damn sound is going through my ears all the time. I miss it... now that thay are gone.

I hoped that friend`s Tom Evans amp will not be able to run 4341 satisfyingly;), but he is in haven, and those are not coming back to me.

Marijan