2308 Lens

[Uncle Paul]

Has anybody tried to make their own?

These are getting harder and harder to find and when you so they are increasingly expensive.

How thick are the plates?

I'm thinking they could be made fairly easily using a pattern. Anybody know what kind of plastic was used or if material (plastic, wood, metal) makes much difference as long as it is rigid enough?

[Ian Mackenzie]

Sounds like a cool project.

You would need to borrow one and measure it very carefully and make a detailed drawing in autocad.

Someone like The Widget may be able to give some tips and on how to go about it...

.......Hey Widget ...are how running off a limited run of 100 pairs for $150-$200 a pair.

I am only joking but it sure would be a fun project.

Ian

[norealtalent]

Replicating them would require a mold due to the interlocking design of each vane. Making something similar to do the job would be much easier if that was all that mattered. Of course the time spent making something that has no original value would far out weigh the cost of simply purchasing an authentic pair. The L94 sounds MUCH better and would be a more worthwhile sonic investment IMO:bouncy:

[Tom Loizeaux]

Why not try to find out from someone associated with JBL the name of the company that made these? They probably still have the mold. JBL isn't interested in stocking these anymore, so they MIGHT allow an indepedent run. ! ?

Tom

[Uncle Paul]

The L94 certainly looks cooler! Appears they aren't completely interghangable, though:http://audioheritage.org/vbulletin/showpost.php?p=84229&postcount=38

In any event I'd like to examine one to see what it would take to fabricate a functional and visual facsimilie. Obviously, this would not be the genuine article.

If someone would be willing to loan me one, even one that is broken, but has enough left to get all the measurements I could at least make the drawings.

I've been looking for a project to give something back to the forum, maybe this is it.

[Uncle Paul]

Tom, just read your post. That is a great idea!

[toddalin]

In any event I'd like to examine one to see what it would take to fabricate a functional and visual facsimilie. Obviously, this would not be the genuine article.

If someone would be willing to loan me one, even one that is broken, but has enough left to get all the measurements I could at least make the drawings.

I've been looking for a project to give something back to the forum, maybe this is it.

I thought that was already a generic knock-off floating around at a greatly reduced cost.

[Uncle Paul]

Any idea who makes them and where to get them?

[frank23]

don't they still make them for the japanese market speakers like the 4344mkII?

I have a perfect pair 2308... but I decided not to sell any of my JBL stuff, sorry

I don't think they would be too hard to make, at least functionally

in essence it is a black plastic rectangle with a certain curve taken out of it in the middle and 11 of them are stacked together a certain distance in a downward way [looks like 45degrees down]

they are put together at the back three times [left, middle, right] and two times on the front [left, right]

so, if you find a CNC machine shop that can program the curve into a machine that cuts these rectangles with curves from [I think] 1.5mm sheetmetal and make 4 identical about 11cm long wooden placeholders with 11 slots in them at 45degrees down at each corner, then you have made yourself a pair of 2308

and that is much easier than asking JBL for the molds and finding a production facility

frank

[4313B]

Part Number is 35202, they are currently out of stock, and the MSRP is $97 each.

[toddalin]

Any idea who makes them and where to get them?

It's been several years and I learned about them from a JBL officionado (sp?) during a transaction, but remember doing some research and finding them at the time. I did a search yesterday for about an hour but came up empty..., but didn't check literally hundreds of potential sites my browser came up with. I seem to remember them being from one of the Far Eastern countries. They were a good representation, but there were minor differences (e.g., thickness of plates, mount).

[majick47]

I'll check my spare parts but I'm almost certain that I have an extra that is "broken" in a few spots but would make a good sample.

[Ian Mackenzie]

Mike Caldwell used to have a stack of those.....some nos ...he might be able to source some more.

[Uncle Paul]

I received a somewhat rumpled 2308 courtesy of Majick47 last weekend that will serve nicely for measurements. (Thank you, sir!)

I did some research and came up with the following:

Plate angle is 38 degrees, coverage is 80 deg H x 45 deg v coverage: http://www.jblpro.com/pages/pub/obsolete/4345.pdf

By measurement, the plates are 1/16" thick and spaced 1/4" apart.

The cutout in the plates is a hyperbolic:
http://www.jblpro.com/pages/pub/obsolete/Acoustic_Lens_Family1.pdf

Due to the difficulty and length of time required to calculate the hyperbolic I'm going to trace the curve on a grid to capture the shape.

This is not an attempt to fully duplicate a genuine injection molded 2307. Instead, these will be plans for an equivqlent DIY copy.

Why do this when they are still reasonably avalaible?

Adds to the collective knowledgebase of the Forum
Fairly simple first project I can use to give a little back for all the Forum has provided me.
Will provide a way for Forum members who can't obtain the genuine article to make their own.
Sooner or later it will become difficult to obtain the real deal. Old ones break every day, and none are being made.
Variety: The DIY lens could be made of metal, plastic in any color or transparancy. The plates could even be veneered if desired.
It's going to be Wet, cold, and rainy in Portland this weekend, so this will keep me from gettin bored when the AFC & NFC Championship games aren't playing (Go Seahawks!).

[Hofmannhp]

Sounds like a cool project.
You would need to borrow one and measure it very carefully and make a detailed drawing in autocad.
....Ian

Hi Ian,

I had the same idea few years ago......ACAD drawing is ready for this.
Main advantage is that all parts are the same.... only glued together.

HP

[Mike Caldwell]

Hello

Funny timing about this topic.
First of all, the pile of the NOS 2308's and the handfull of used I had
have long since been sold.
However I have found a company that produces a wide range of horns and wave guides that is interested in looking at a 2308 to see what it would take to get set up to make a run of them.
I have been looking for a used 2308 that I could send to them, condition is not all that important, any one have one for sale or loan.
Of all the 2308's I have had and now I need to find just one!


Mike Caldwell

[toddalin]

Hello

Funny timing about this topic.
First all of the pile of the NOS 2308's and the handfull of used I had
have long since been sold.
However I have found a company that produces a wide range of horns and wave guides that is interested in looking at a 2308 to see waht it would take to get set up to make a run of them.
I have been looking for a used 2308 that I could send to them, condition is not all that important, any one have on for sale or loan.
Of all the 2308's I have had and now I need to find just one!


Mike Caldwell

They continually show up on ePay. Sure it's going to cost a few more $$$ that way, but that's a tiny portion of the ultimate cost that it would take to bring such a product to market. R&D costs.

[glen]

I thought that was already a generic knock-off floating around at a greatly reduced cost.

I remember years ago getting some dirt cheap plastic reproductions from a company called Image *something*
Image Audio?
Image Electronics?
They also sold the Waldom recone kits, and many brands of speakers/drivers at semi-wholesale prices.

Ring a bell with anyone?

[andresohc]

I have a beat up one I could send you. PM me if interested

[toddalin]

I remember years ago getting some dirt cheap plastic reproductions from a company called Image *something*
Image Audio?
Image Electronics?
They also sold the Waldom recone kits, and many brands of speakers/drivers at semi-wholesale prices.

Ring a bell with anyone?

In a prior thread I also mentioned that there was a gent who informed me about the reproductions, and I actually remember seeing them on the 'net at the time. The reproductions had slight variations such as the width of the plates, and maybe the count differed by one. I spent quite a bit of time searching the web for these a couple weeks ago and came up empty.

[Ian Mackenzie]

You can still buy the Lense from JBL a previously post by Giskard.

I don't know the stock situation though.

I worked out why so many are chipped, they have a habbit of falling off.

[frank23]

I found these pics of speakers with nicely made copies of 2308's on a japanese website

frank

[glen]

Has anybody tried to make their own?

Another Japanese custom 2308 style lens on 4355s.
Looks like it's made of wood.

http://www.geocities.jp/nobita_desu_uchino_neko_aoiyo/img/dcx2496-4.jpg

[johnaec]

All we see is a red X. I don't think Geocities allows linking to pics at their site - if you see it it's probably in your Internet cache. Save the pic to your computer and the attach it to the message. Or it can be viewed if you directly paste the link into your browser.

John

[Val]

I love this thread as I've been looking for an acoustic lens for my LE15/375/075 project and have thoughts of making something. I like the Japanese knock off. Looks like it would never fall off or chip!

[hjames]

I didn't see the image either - so I downloaded that wood lense image from Geocities Japan - and it was over the filesize of 390k (1024px wide, too!) so I resized it to 2/3 and am uploading the resulting 200k file so its available to all readers of this thread.
Original image is at: http://www.geocities.jp/nobita_desu_uchino_neko_aoiyo/img/dcx2496-4.jpg

(One problem with the free Geocities accounts is that they have hourly bandwidth limitations that will block the site once the hourly limit is reached)

[toddalin]

I love this thread as I've been looking for an acoustic lens for my LE15/375/075 project and have thoughts of making something. I like the Japanese knock off. Looks like it would never fall off or chip!

I have a pair of Champagne HL89s horns and lenses where one lens was narrowed to 15-1/4" so the guy could mount it above a 15" woofer on a narrow baffle. The other lens has a hacksaw cut in the back of one of the wavy plates, but if this lens were also narrowed to 15-1/4", the cut would be on the exces waste piece. Other than that, they are in good shape with no dents or bends.

I'll let the set of four (two horns and two lenses) go for $375 plus shipping from 92705 to a LH member. Would make a nice project for someone.

[paragon]

Doesn`t fit :biting:

http://img479.imageshack.us/img479/4364/isophonlens18sz.th.jpg (http://img479.imageshack.us/my.php?image=isophonlens18sz.jpg)

[wpod]

If anyone is interested, Image Communications in Bedford Park, Illinois has some of these lenses available. They were originally part of their Epitome Accessories listed as "Lens L-11 Plastic Deflection 10 layers 10"w x 3.5"h x 5.5" Overall Height". There is a tiny picture in their catalogue that suggests it looks like a 2308 lense. I called them to find out if they still had stock available but unfortunately they don't. HOWEVER ,They now carry the L-10 lens which has nearly the same dimensions (which I seem to have misplaced). In any case, if anyone is interested in a set, they are $9.00 per lense. I don't know if Image will sell to the general public, but I still have an account there so I'd be glad to be of assistance if necessary. I beleive that they also have a $50.00 minimum purchase. No website.

[glen]

If anyone is interested, Image Communications in Bedford Park, Illinois . I don't know if Image will sell to the general public, but I still have an account there so I'd be glad to be of assistance if necessary. I believe that they also have a $50.00 minimum purchase. No website.


Thanks for dredging up the name & location wpod. I placed a $50+ order with them years ago, they had so much fun stuff in their catalog it was REALLY EASY to exceed that minimum.

maybe it's time for me to get another catalog...

[Earl K]

If anyone is interested, Image Communications in Bedford Park, Illinois has some of these lenses available. They were originally part of their Epitome Accessories listed as "Lens L-11 Plastic Deflection 10 layers 10"w x 3.5"h x 5.5" Overall Height".

I bought a bunch of those L-11(s) at least 12-15 years ago . Somewhere, I still have at least one original L-11 cardboard shipping box. They are/were made in Taiwan. Came stuffed with shredded taiwanese newspaper. They're a very close copy of the JBL 2308 lense. Epitome ? , also made a 2307 knockoff which I keep around here for testing purposes .

:)

[Val]

If anyone is interested, Image Communications in Bedford Park, Illinois has some of these lenses available. They were originally part of their Epitome Accessories listed as "Lens L-11 Plastic Deflection 10 layers 10"w x 3.5"h x 5.5" Overall Height". There is a tiny picture in their catalogue that suggests it looks like a 2308 lense. I called them to find out if they still had stock available but unfortunately they don't. HOWEVER ,They now carry the L-10 lens which has nearly the same dimensions (which I seem to have misplaced). In any case, if anyone is interested in a set, they are $9.00 per lense. I don't know if Image will sell to the general public, but I still have an account there so I'd be glad to be of assistance if necessary. I beleive that they also have a $50.00 minimum purchase. No website.

After a bit of a run around, Image Communications agreed to sell a private party the L-10 lens. I need two for my current project. I ordered 6 to make the minimum order...supposed to ship tomorrow. Once I get them I will post images.

[Val]

I was prepared for anything, especially with a price of $9. I'm very pleased with what I recieved. 3 mounting holes on each side. Looks like each slat is individually molded and then glued into the stack. The mounts are then glued on. They seem sturdy. Sort of a molded in matte finish. They come in a plastic bag.

Thanks wpod for the lead and all for your comments.

While I'd love to have original JBL (and maybe one day will) these will serve.

[John W]

Has anyone gotten anywhere making their own copy of these?

[boputnam]

I didn't see the image either - so I downloaded that wood lense image from Geocities Japan - and it was over the filesize of 390k (1024px wide, too!) so I resized it to 2/3 and am uploading the resulting 200k file so its available to all readers of this thread. It's a good thing you did, madam - the image is now gone...

But what to do about those walls, and that floor!! :banghead:

[John W]

Those are beautiful.

I guess what I am looking for are scale drawings of the fins so I can make my own.

[Mr. Widget]

Those are beautiful.

I guess what I am looking for are scale drawings of the fins so I can make my own.Are you talking about the lenses on the 4355s in Bo's post? I know the fellow and could probably get some info for you.

Bo, he solved the problem... he recently moved.:D


Widget

[John W]

Actually I was looking for the current 2308 design.

If someone knows more information about the lenses in Bo's post that would be interesting too. Why aren't they a straight parabolic profile, and why are a couple of the fins shorter than the others?

[Alex Lancaster]

:( I shopped around, and the injection is close to nothing, but a pro mold would be about $5,000 US, so I dropped the project; What is Image comm.'s address?, an 800 tel number won´t work from here, Thanks.

[Mike Caldwell]

Hello
For a few months I have been persunig companies that could make the plates for the 2308 lens. With a old 2308 sample that was sent to me from fourm member "andresohc" that I sent to many companies for evaluation and pricing with really no luck or interest, some were only interested in doing production runs in the 10's of thousands! I now a full 3D cad file of the plate from a 2308 lens and have sent it to company that sounds like they will be interested in doing a lower number run. I noticed the other lens from Image Communications only had 10 plate instead of the JBL's 11.

I'll let you know if my lens production pursuit comes together.

Mike Caldwell

[boputnam]

What about Widget Works? They certainly could :yes: :yes: :yes: , but it would be far more valuable than the orginals!

Now Widget will whack me, for sure. :duck:

[Mr. Widget]

The 2308 requires a very simple tool. (THat's what an injection molding mold is called) You only need one flat tool and then you will need to shoot 11 parts for each lens. If you made 100 lenses that would mean shooting 1100 parts... almost enough to make it worthwhile.

If you are interested I can hook you up with folks in Asia that could make a tool and shoot the parts very economically... they would probably throw in gluing them together and bagging them for surprisingly little.

The question is, is there really any demand for these things? I can see buying a pair on eBay for $125 to restore a vintage system, but otherwise why would you want them?


Widget

[schloerch]

It's a good thing you did, madam - the image is now gone...

But what to do about those walls, and that floor!! :banghead:

After having bought my monitors without the 2308 lenses I was forced to search for something equivalent.
Those I found Japan and they are working on my 4345's. these are made of ebony-wood and look perfect.They were produced by the same guy who made the lenses on the 4355's.

[mbd7]

Could you be so kind as to post a link or some contact information for the maker of these great looking specimens. Do they sound as good as they look?

[mbd7]

Could these be retro-fitted on to a pair of 4343's? One of these lens is a little beat up but other seems alright from the pictures.

http://cgi.ebay.com/McCauley-417-horn-lens-pair-for-JBL-375-2440-H93-2392_W0QQitemZ9725267125QQcategoryZ50597QQrdZ1QQss PageNameZWINQ3aPOST0Q3aRECOQ3aBIDQQcmdZViewItem

[Ian Mackenzie]

Wow, I really like those wood horns.

I might have to surf some Japanese hifi stores soon.

[takenodisk]

Can someone please explain me how do you get through on theese japaneese web sites such as yahoo auctions as all those adds are described in japaneese,is there a trick or something cos my computer only displays cubic icons:dont-know

[glen]

Can someone please explain me how do you get through on theese japanese web sites such as yahoo auctions as all those adds are described in japaneese,is there a trick or something cos my computer only displays cubic icons:dont-know
I usually will go to:

http://www.yahoo.co.jp/

and search from there for "jbl" etc.
The yahoo auctions are always high on the results list

Unless you have downloaded the Japanese character sets (big, slow dowload) you will see lots of cubes with letters/numbers in them (I think these are hexadecimal representation of a Japanese character set just as the ASCII character set translates hexadecimal values as english characters)

But in my experience the cubes are still translated just fine by Altavista/Babel fish:

http://babelfish.altavista.com/

I will usually try to enter the web address URL into the bottom "Translate a Web page" field, set the from/to languages for Japanese to English, and press the translate button.

This works OK for most websites, Harman Japan for instance:

http://www.harman-japan.co.jp/

But not as well for some of the more gimmicy web pages, yahoo auctions for instance.

In that case I will copy the japanese text into the "Translate block of Text" entry box which usually does a fair job with most of the text, for instance:

★JBL ★ 2WAYスピーカー★ SVA1800★＋おまけ


中古品です
多少のキズ、使用感有るとみてください
大きさ318×965×413mm
重さ34kg
スピーカー部破れなどありませんが
多少独特の粘りっぽくはなってます
オマケはモンスターケーブル5ｍを４本です（中古）
これだけでもお得だと思います
写真をご参照下さい
ご理解いただける方
ご入札お待ちしております

発送はヤマト便です
東京は西荻窪にて西洋アンティーク・和家具
リサイクルのショップを営んでおります。
ホームページにてネットショッピングも出来ます。
是非ご覧ください！

http://www.antiquesjikoh.co.jp

お探し物、リクエスト商品などありましたら
こちらまでメールでお知らせください

■注意！■

最近私どもの名を語る繰上げ落札の
詐欺行為が多発しております
こちらではそのような行為は一切関与しておりません
アドレスとＩＤを確認し、
ご不安であれば我が社のホームページより
お電話、メールにてお問い合わせ下さい

was translated as:

* JBL * 2WAY speaker & SVA1800 & + being defeated Are the used item please see the size 318×965×413mm weight 34kg speaker section tear etc. which there is no, that some scratch and there is a use impression, but as for some unique stickiness っ ぽ く becoming, as for オマケ which it increases monster cable 5 m 4 is, the one bid which reference understanding, it can receive the photograph which you think that (medieval times) even just this is profit, we wait As for dispatch Yamato flight as for Tokyo which is the west reed 窪 being similar, we operate the shop of western antique harmony furniture recycling. At the home page also net shopping is possible. Please view by all means! Http: //www.antiquesjikoh.co.jp When the missing article and the request commodity etc. it is, to this please inform with the mail * Note! * Recently though me if with this where fraud behavior of the advance successful bid which talks name occurs frequently as for that kind of behavior address and ID which have not participated altogether are verified and it is insecure, at the telephone and the mail please inquire from the home page of our corporation

[takenodisk]

Hi glen,great you spares me some japaneese tuition:) thanks a lot, i wouldn't have thought about this for a moment,i'll give it a try as soon as i'm back home,bests Mevin

[takenodisk]

Hi Glen it works great,it's incredible,i'm watching actually(just watching)a pair of 4344 on yahoo jp which is actually going for nearly 3800usd,thanks:applaud: again

[Val]

:( What is Image comm.'s address?, an 800 tel number won´t work from here, Thanks.

Waldon Electronics (distributor for Image Communications)
1801 Morgan St
Rockford, IL 61102
815-968-9661 x4293
Sandy Freeman helped me
9$/each L-10 Plastic Lens
$50 minimum

[mbd7]

I talked with Sandy yesterday an she said that the L-10's are gone and they aren't going to make any more! So it's back to the other avenues we've been discussing for years. So do you guys think that the McCauley lens could be fitted to a 4343?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9729824973&fromMakeTrack=true

[Steve Schell]

Some of you might remember that I posted pics of Bart Locanthi's original prototype of the 2308 a while back. This piece belongs to a friend of mine, but I still have it on hand. If anyone wants more detailed information on it then I will do what I can. It is held together with brass machine hardware; two long screws running through with nuts threaded on to space the plates apart.

[mbd7]

I counted 15 vanes on this lens but I'm sure it's a hell of a lot easier to loose a few than try to find a couple extra.

[John W]

I borrowed an older model 2308 from a friend and recreated a pair using dark grey PVC that I got from TAP plastic. PVC is fairly easy to saw and shape on the router. I glued it up with some PVC plumbers glue. They are sturdy and turned out quite nice for the modest investment.
I am not sure the method I am going to use to mount them yet.

[mech986]

Very Nice!! How did you make the mount that holds them at an angle?

Regards,

Bart

[John W]

Very Nice!! How did you make the mount that holds them at an angle?

Regards,

Bart

I created a seperate jig used for the glue up. The jig started with a block cut with 1/16 inch grooves at a 38 degree angle. The fence was moved 1 centimeter after each cut.
Basically, I cut the plate rectangles a couple inches long, about 3 x 12. I bolted about 6 at a time together with my form using holes drilled threw the extra outside area. I cut the parabolic cutout using a saw and pattern router. I cut two grooves on the back. Removed them from the form and cut to length - 3 x 10
I then made some spacers and glued them onto each plate. Then using the setup jig, glued the plates with the connected spacers together. On the back, the grooves have strips of the PVC material glued in.

[John W]

Here is a picture of the jig.

[loach71]

Here is a picture of the jig.
Your beautiful workmanship makes me feel like I am all thumbs :o:

[kodomo]

Hello. this is my first time to write here. The wooden lenses with 4355s are my items. The lenses are made by my acquaintance. If someone want it, I can do business with instead of him. Also I have some grill emblems(replica) for sale. 4343, 4343B, 4344, 4345, 4355 is in stock. They are $80.00 per pair + $15.00 shipping(ship to anywhere via EMS). And 4343 foilcal(replica) is same price. Please email me if you are interested.

[majick47]

They all look beautiful! Would you have any grill emblems for the 4301B?

[kodomo]

hi majick47,

Sorry. I have only them which is on the list. But if you send me scanned image of original emblem, I will make it. Since initial cost is necessary to make first product, you must buy more than 4 pairs($320). The items is very high quality and recommended. Thanks.

[grumpy]

While over at "toddalin's", Todd was kind enough to let me have a look at
a stock lens. We took some measurements and a trace... thinking I might
follow in JohnW's footsteps regarding a DIY lens. I couldn't leave well enough
alone and fit a hyperbolic curve to the measurements (not everyone has a
lens to trace). Pic attached, ignore the ellipse in the center. Have fun.

-grumpy

[kodomo]

Hi,

The plan of the reproduction of JBL 2308 lens was finally completed. I listed them on ebay (http://shop.ebay.com/items/_W0QQ_dmptZVintageQ5fElectronicsQ5fR2?_nkw=jbl+230 8+acoustic+lens&_sacat=0&_fromfsb=&_trksid=m270.l1313&_odkw=jbl+2308+lens&_osacat=0).:D

[Mr. Widget]

The plan of the reproduction of JBL 2308 lens was finally completed.Funny how a seemingly simple project like this can take so long. :)


Congratulations! Very nice work!


Widget

[JBL Dog]

I think they will sell quite well at $130 a set. Very nice work!!

:applaud:

[4313B]

I think they will sell quite well at $130 a set.That's a really nice price. Current JBL MSRP is $193.18 a pair but they are out of stock and something tells me JBL isn't going to bother with another run.

[grumpy]

Look great in the pics, we'll see for certain in a few weeks :)

[grumpy]

Shipping, notification, and packaging were great.

The units are reproductions to a very high level of detail.

I await a PM response from the manufacturer before posting my own
comparison (stock vs. repro) pictures.

[toddalin]

Shipping, notification, and packaging were great.

The units are reproductions to a very high level of detail.

I await a PM response from the manufacturer before posting my own
comparison (stock vs. repro) pictures.

From the pics, other than the obvious color difference, the notable difference to me is the crispness of the backside right-angle corners. The repops look slightly rounded/beveled there to me in the pics.

I note that there is no picture that compares absolute length back-to-back, but was assuming this would be an easy part.

[grumpy]

The color diff in the photo, I suspect, is more due to lighting and very
minor surface micro-texture differences... the plastic material itself appears
to be very close (at least when the 2308 is clean :)).

The corners are as sharp as the original JBL (plastic) version I have on loan
from Todd.

Dimensions of the basic lens plates are identical, with possible exception
of thickness... close enough that I'd need to get out the calipers to be sure.

The hyperbola execution is very close, probably less than 1/32" at any
comparison point... this is only (barely) noticeable when the lenses are
stacked (they fit well enough to do this) and viewed with the profiles
in-line (top view, considering normal use).

I have only one area of comment that isn't "absolutely fantastic", and as
I'd like to see this endeavor succeed, I will wait for the vendor's reply
before elaborating, as it seems resolvable.

[grumpy]

... resolvable or ignorable. My one -minor- concern is actually visible on the
first, vendor provided photo (post #64, above). I did not notice it
initially. Even if you can find it, I still expect you will be very pleased with
the quality of this product.

If you enjoy "Where's Waldo?" books, read no further.


Otherwise, just realize that a very few of the lens plates may not be
-perfectly- flat... a very minor and cosmetic-only issue that is difficult to
spot. It is not worth posting additional photos to highlight the result...
which is a minor variation in lens plate spacing at the front/cutout
intersection. The vendor is aware of the issue and has made efforts to
minimize the problem before (tossing bad plates) and during assembly.

If I can find a method to permanently tweak/adjust the plate spacing
without damaging the assemblies I have purchased, I'll be happy to share
the procedure. I may just leave them alone.

So why mention it at all? The JBL product had no such noticeable
variations, although I'm sure even their initial run had it's own issues to
sort out as the manufacturing and QC processes were refined.

The product remains highly recommended.

-grumpy

[toddalin]

... resolvable or ignorable. My one -minor- concern is actually visible on the
first, vendor provided photo (post #64, above). I did not notice it
initially. Even if you can find it, I still expect you will be very pleased with
the quality of this product.

If you enjoy "Where's Waldo?" books, read no further.


Otherwise, just realize that a very few of the lens plates may not be
-perfectly- flat... a very minor and cosmetic-only issue that is difficult to
spot. It is not worth posting additional photos to highlight the result...
which is a minor variation in lens plate spacing at the front/cutout
intersection. The vendor is aware of the issue and has made efforts to
minimize the problem before (tossing bad plates) and during assembly.

If I can find a method to permanently tweak/adjust the plate spacing
without damaging the assemblies I have purchased, I'll be happy to share
the procedure. I may just leave them alone.

So why mention it at all? The JBL product had no such noticeable
variations, although I'm sure even their initial run had it's own issues to
sort out as the manufacturing and QC processes were refined.

The product remains highly recommended.

-grumpy

Ahhhh,

The spacing between third and fourth is greater than the spacing between the fourth and fifth from bottom on left. :coolness:

On motorcycle engines, there are sometimes rubber spacers or plugs between the cooling fins to dampen vibration. Something like that could be adapted, though it would place small obstructions in the signal path. The tension of the rubber would hold them inplace. Not original though.

[grumpy]

rubber spacers or plugs between the cooling fins...

Was thinking along the lines of applying fairly localized heat while the
plates were held at the proper spacing (jig or spacers). Getting -controlled-
heat just to the area of interest will be a trick. It would certainly be much
simpler if the plates were not glued together, but it -appears- that the
bonding agent "melts" the parts together... like model glue. I'd be happy
to be corrected, especially if non-destructive dis-assembly is possible.

[Mr. Widget]

Look great in the pics, we'll see for certain in a few weeks :)Today I received my pair. The level of professionalism is outstanding. The packaging, the manufacturing, even the label with serial number... very impressive.

I do not have a pair of originals for comparison, but I am confident that when installed no one would ever mind that they were not made by JBL. I am certain that they will be identical sonically, and visually they are very nice. My only criticism is that the mold flow lines in the injection molding process are visible... probably something that most wouldn't even notice. For myself, I'll shoot a quick coat of Kyrlon Semi-Flat black paint on the top vane. It'll take a few seconds and make them look perfect.

I'd recommend these to anyone with a broken or cracked L91 or 2308 lens.


Widget

[Fangio]

Today I received my pair. The level of professionalism is outstanding. The packaging, the manufacturing, even the label with serial number... very impressive.

I do not have a pair of originals for comparison, but I am confident that when installed no one would ever mind that they were not made by JBL. I am certain that they will be identical sonically, and visually they are very nice. My only criticism is that the mold flow lines in the injection molding process are visible... probably something that most wouldn't even notice.

...

I'd recommend these to anyone with a broken or cracked L91 or 2308 lens.

Widget

Got a pair out of Kenji's second batch of these lenses, currently available again.

So far I have had four pairs of originals in more or less used condition for comparison, have kept two intact pairs. I would consider myself picky, and it's quite possible more JBL speakers in need of undamaged lenses will come by in future.

Anyway, these Kenrick lenses are as good as it gets now and look brandnew of course. I personally won't bother about looking for „mint” originals anymore, I'd just order another pair from him and be done. Handling and shipping to Europe was professional as well.

Highly recommended.

[macaroonie]

In this day and age it is great to hear of a transaction without disappointment.
:applaud:

[brad347]

Just bumping this thread to ask a question--

To those who ordered lenses from Kenrick via eBay, how long was it before you received any kind of notice or communication re: "order received" or "shipping information" etc.?

[grumpy]

I didn't expect them right away, so I wasn't worried about it.
They just showed up without notice, IIRC.

[brad347]

They just showed up without notice, IIRC.

Cool-- that's what I wanted to know!

Thanks.

[ivica]

While over at "toddalin's", Todd was kind enough to let me have a look at
a stock lens. We took some measurements and a trace... thinking I might
follow in JohnW's footsteps regarding a DIY lens. I couldn't leave well enough
alone and fit a hyperbolic curve to the measurements (not everyone has a
lens to trace). Pic attached, ignore the ellipse in the center. Have fun.

-grumpy

Thanking to Grumpy work and figure approximate hyperbola curve that can be fit can be written as:

36*x*x - 64*y*y = 9

so asymptote angle Q to x-axis is about 36.87 deg, or
cosQ = 0.8
sinQ= 0.6
or tanQ = 3/4

[ratitifb]

36*x*x - 64*y*y = 9

so asymptote angle Q to x-axis is about 36.87 deg, or
cosQ = 0.8
sinQ= 0.6
or tanQ = 3/4and what about ln(tanhQ) ? :D

[maxserg]

Could these be retro-fitted on to a pair of 4343's? One of these lens is a little beat up but other seems alright from the pictures.

http://cgi.ebay.com/McCauley-417-horn-lens-pair-for-JBL-375-2440-H93-2392_W0QQitemZ9725267125QQcategoryZ50597QQrdZ1QQss PageNameZWINQ3aPOST0Q3aRECOQ3aBIDQQcmdZViewItem
I have those horn/lens fitted with 2420 JBL drivers(pair) They are made of steel ant they have endured lots of tours, still rockin':D

[ivica]

and what about ln(tanhQ) ? :D
well, if You want to make yourself these data would be useful