2235 Break in Time

[Rolf]

Of course you can find recone kits in Norway!

But the 2121, 2121H or 2122H is very hard to find.

Guido

Hi GUdio

If you mean the basket/complete speaker, I don't really know. I have never tried to find one. But remember, from the late 60's and to the mid 80's there was sold quite a lot professional JBL's in Norway.

I an trying to get my hands on 4350 or 4343, but so far no luck. I would perfer if they are somewhere in Europe, as I expect quite a freight bill to get them from the US.

Can you recommend good European sites where used hi-fi is sold?

Rolf

[Guido]

Hi Rolf!

I bought my original 4343 cabinets + 2420 drivers incl. horn + X-overs original + 2405 slot tweeters original from www.ebay.de.

The only things missing are pair of 2235H (2231A) and 2121 or 2122.

But I'm shure I will find them soon. I'm on a few tracks.

I can't wait to hear my 4343.

Guido

[Niklas Nord]

Giskard how do you break in the drivers?
20hz at 10 volts you say, with an ampfilter
and test tone ?

or some instrument?

[4313B]

Yes, an amplifier, an audio oscillator, and a volt meter.

[locanti]

Originally posted by Earl K
Always best to have a Pro evaluate the woofers condition ( that would involve, at the very least, an Fs measurement , a visual inspection and a proper tone sweep - would be nice to get an impedance curve ). Again, a recone is a lot easier .

regards <. Earl K [/B]

Thanks Earl for your advice

It's not so easy to have an expert opinion here in France.Dealers just want to sold you new loudspeakers even if yours are still usable.So we have to do business by ourself.

I'm an electronician(Work in a phone company)and I recone loudspeakers for years(When I found the recone kit)I have the equipment to measure FS and to draw an impedance curve.( sound generator,Impedancemeter,oscilloscope and more)

The 2 Le10A have an FS of 83HZ an 96,5Hz.I used them in C53 libra cabinet(Copy) and the sound have no bass at all(It seems to me than few years ago the sound was deeper)

Does it worth the money to recone them?

Regards

Bert

[Earl K]

Hi Locanti

Originally posted by locanti

The 2 Le10A have an FS of 83HZ an 96,5Hz.I used them in C53 libra cabinet(Copy) and the sound have no bass at all(It seems to me than few years ago the sound was deeper)

The Fs on those speakers should be 30 to ( 40 hz on the high side ) for arguments sake. You will certainly not be getting the bass you used to get with Fs values that high. Try , one ( time only) DOT 3 brake fluid treatment to see where the Fs ends up .

Does it worth the money to recone them?

Try the brake-fluid method first with the thought that if you mess it up and it doesn't work out , then you must spend the money on the recone kits .
I happen to like the aquaplas dampening of these speakers so much that I'm likely to buy a pair of recone kits to keep around for the future upgrades & projects . But, at only @ 90 db/watt you have to answer that question of accumulation for yourself. I'm using these with the less sensitive le14 woofers. A lot of others prefer to build projects that are mid 90 ( db ) effeciencies using 2235s/ 2245. That dictates going to the 2121, 2122, 2123 range of 10" midrange speakers to match sensitivities. I'll probably order some kits after the Canadian dollar strengthens some more against the US dollar . Right now the Euro $ is in good shape vs the US $ so maybe nows a good time for you to order. Predicting currency exchange rates is virtually impossible ( if one could, some of us would be rich )


Regards <. Earl K

[locanti]

Hi Earl

I suppose it's easy in US to find replacement kit for JBL Le10 drivers but in Europe it seems that only the professional series speakers kit are available.Where can I found kits on the Web?Do you know some shop that sell overseas?

[Doctor_Electron]

Yet another Dr_Electron-length post...
I worked for a JBL pro service center, and would like to share with you what you get for your $$ on an authorized re-coning.
My personal involvement in the process (on other than my own components) mainly consisted in cleaning the frames and checking them for gap cleanliness & gap concentricity/width, as the owner was very particular (nearly to the point of obsession, partly a control freak issue, partly a perfectionist issue) about re-cone jobs being properly done there.
The re-cone starts with removal of all the old cone/spyder/surround residue & glue from the woofer frames (yes, MEK is the ticket, although it barely fazes the newer epoxies, as found on the 127H, etc.), Lots of elbow grease and very sharp chisels & bearing scrapers seem to be all that works on them.
The voice coil gap must now be perfectly clean, and is checked with the appropriate gap gauge (non-magnetic beryllium/copper or martinsitic stainless steel, JBL part #, $$).
Now a JBL factory recone kit is installed via the use of an alignment tool in the form of a thin but very rigid plastc cylinder, which is placed squarely in the magnetic gap. The cone /spyder assembly is then slid over this cylinder, and the spyder is glued, followed by the gluing of the cone surround to the frame. While the glue is not quite fully hardened, the new cone's voice coil is carefully moved in and out of the gap to check for rubbing. Once this alignment is adjusted and checks out OK, the glue is allowed to harden, after which the alignment cylinder is removed. The dust cap is glued onto the cone, and the voice coil's "tinsel leads" are soldered to the connector posts. Following this, another "externally applied" (by hand, that is) cone motion re-check must be done (no VC rubbing again), and finally the driver gets a short series of impedance, frequency sweep, and electromechanically applied motion & response tests.
What I would consider a proper cleanup on a 2235, for example, can easily take 1/2 hour to accomplish. Another 1/2 hour to an hour for a good cone layup, dust cap, & solder job, and 15 min. or so for the final tests.
The genuine kits are not cheap, even to the dealer...I paid cost and shelled out about $180 for two 2235 kits. Non employees pay 7.5% tax on the $90 parts (three years' ago jobber price) plus any nominal mark-up on these materials.
The crux of this long-winded diatribe is... when you pay $150-$170 or so for such a driver re-cone, it is a fair price and represents great value when you consider the materials cost, expertise & tooling required...plus you get the 90 day "as new" warranty coverage in case there IS a problem afterwards. An hour or so of "Sweat equity" made as a do - it - your - selfer is a great labor of love to be done, but the repair center is a business with overhead costs, and everyone has to eat and have shelter. Getting an authorized factory certification in the first place is a fairly pricey matter, with training time and a pretty huge investment in an initial minimum parts inventory purchase is required, and the needed fixturing and non-magnetic tools must be purchased from JBL, and they AIN'T cheap...trust me on THIS! You must buy a set of gap gauges & alignment fixtures for each size and/or series of JBL drivers, as part of the startup "qual".
All things considered, I would just about toss it up as to whether I would do my own recones or just pay another pro.
Anyhow, that's how it all looks from here. Good Luck, ya'all.

[Rolf]

Originally posted by Doctor_Electron

I worked for a JBL pro service center, and would like to share with you what you get for your $$ on an authorized re-coning.
The genuine kits are not cheap, even to the dealer...I paid cost and shelled out about $180 for two 2235 kits. Non employees pay 7.5% tax on the $90 parts (three years' ago jobber price) plus any nominal mark-up on these materials.
The crux of this long-winded diatribe is... when you pay $150-$170 or so for such a driver re-cone, it is a fair price and represents great value when you consider the materials cost, expertise & tooling required...plus you get the 90 day "as new" warranty coverage in case there IS a problem afterwards.
Anyhow, that's how it all looks from here. Good Luck, ya'all.

Hey!

Nice! The job here in Norway cost about US$ 300 each. It's worth it!!!

Rolf

[Earl K]

Hi Locanti

Originally posted by locanti

I suppose it's easy in US to find replacement kit for JBL Le10 drivers but in Europe it seems that only the professional series speakers kit are available.

Well , I'm in Canada and the situation here is somewhat similar to what you experience, lots of JBL Pro service, but HiFi service is quite limited . Giskard ( briefly ) pointed out that this cone-kit is still made ( once in a while ) and is available but is now back-ordered. I believe that means that when JBL reaches a " threshhold " number of orders, then & only then will they make up a batch & then ship them out . I have no idea how long an "ordinary wait" might be . I had an order in for a pair of le10 cone kits last fall ( Nov.). Waited about 2 months before cancelling my order. The production run hadn't started yet so I didn't pay any financial penalties . Now it seems, that the run was never executed ( from this vantage-point ) .

Where can I found kits on the Web?Do you know some shop that sell overseas?

As far as I know you can't buy authorized JBL kits from any web-site. I've never looked, I don't recone and really don't want to have to . Consider dropping Giskard a private email and ask him what is possible and do-able for a situation like yours .

regards <> Earl K

[obsessed?]

My first posting:I've been a speaker hobbyist and JBL 'le' owner for thirty five years. That said, I don't know much, really. I don't know exactly where this posting will end up, but I wanted to share a material/method for repairing surrounds that I discovered on my own, I'm probably not the first, but I haven't heard of this particular product being used on speakers before.
A flowable silicone, NOT the pasty window and door stuff, is available through auto parts stores. Sold as a windshield and glass sealant, it's makers, Permatex, have told me that it is not available in quantities larger than the 1.5 oz tube (item no#81730).
This stuff can do amazing restorations, though not super pretty ones, for rotting foam surrounds. The material tends to flow and smooth itself out, so at least it is not lumpy when cured. As long as you can lightly touch the foam surround without it crumbling, with a steady and careful hand you can make that surround into a durable silicone speaker edge. A small artist's paint brush is the best tool I have found to spread the silicone evenly, with a light touch, around the surrond.
Lansaloy hardens and cracks rather than crumbling, so for these speakers this material will only bridge the fissures and hold the edge together.
The best use of his stuff is probably the repair of drivers that are not worth reconing or that you can't afford to recone until later. Please reply, especially if you have good results or other uses for this product. Good luck!
Also if anyone has good advice on getting my 40 something year old
LE8's (no 't') reconed (i'm interested in having the best high end sound I can) please respond. Thanks.

[sdaniel]

Maybe, but I also sincerely want to know about break in. I am awaiting delivery of the LSR 63 series components needed to for my home theater, and want to know how I should break them in, and how JBL normaly conveys that info to the customer. I remember setting up my brand new 4410's and not being to happy - but the book or dealer never said anything about break in! I simply tweaked the tone controls, had a beer and cranked them up, which worked, but may not have been the best approach.




Thanks,
Sdaniel

lsr 25 p x 2 rear
lsr 6328p x 1 center
lsr 6332 x 2 front
lsr 6312sp x 2 subs

[JonathanKeehn]

I have a pair of LE 15's reconed with 2231 cones for better power handling capacity. After 10 years the foam surrounds started splitting where the surround meets the cone edge causing a buzzing on hard bass notes. Rather than ship them off to JBL for a recone I decided to apply some common rubber cement along the split line about 1/8" either side and see what happened. The repair worked very well with no discernable difference to my ear except that the buzzing was cured. I regularly drive my L-300 style system to 300 watts per channel which is about double the woofer's capacity. To my ear the resonance frquency has changed very little and I will keep that $ 2.00 bottle of rubber cement handy if I need it. One woofer has a split from the 3 0'clock position to the 6 o'clock position which is a quater of the total surround circumfrence. I personnaly wonder if coating the entire surround would affect the Fs that much. If any of you have a similar situation this solution might be worth a try.

[edgewound]

I have a pair of LE 15's reconed with 2231 cones for better power handling capacity. After 10 years the foam surrounds started splitting where the surround meets the cone edge causing a buzzing on hard bass notes. Rather than ship them off to JBL for a recone I decided to apply some commmon rubber cement along the split line about 1/8" either side and see what happened. The repair worked very well with no discernable difference to my ear except that the buzzing was cured. I regularly drive my L-300 style system to 300 watts per channel which is about double the woofer's capacity. To my ear the resonance frquency has changed very little and I will keep that $ 2.00 bottle of rubber cement handy if I need it. One woofer has a split from the 3 0'clock position to the 6 o'clock position which is a quater of the total surround circumfrence. I personnaly wonder if coating the entire surround would affect the Fs that much. If any of you have a similar situation this solution might be worth a try.

Whoever decided to recone your LE15's with a 2231 kit obviously didn't pay attention at recone training or read the manual. Those two cone assemblies are not interchangeable...never have...never will be.

But some people don't believe the factory. Drives me crazy.

These are the kinds of posted info that drove Giskard to the edge.

[JonathanKeehn]

Even with non-recommended cones my system sounds fantastic. When these drivers finally go, I will simply replace them with 2235 H's or with the 1500 AL - God forbid if JBL ever sells them in the US.