+ Reply to Thread
Page 1 of 6 123 ... LastLast
Results 1 to 15 of 84

Thread: 2308 Lens

  1. #1
    Senior Member Uncle Paul's Avatar
    Join Date
    Feb 2005
    Location
    Oregon City, Oregon, USA
    Posts
    374

    2308 Lens

    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?
    "Zobel is as zobel does"

  2. #2
    Senior Member Ian Mackenzie's Avatar
    Join Date
    Apr 2003
    Location
    The Tardis
    Posts
    5,951
    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

  3. #3
    norealtalent
    Guest
    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
    Last edited by norealtalent; 01-03-2006 at 06:05 PM. Reason: grammer, can't speak in english, como esta pole vu france?

  4. #4
    Your Memory Lives On RIP Tom Loizeaux's Avatar
    Join Date
    Apr 2003
    Location
    Baltimore, MD USA
    Posts
    669
    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

  5. #5
    Senior Member Uncle Paul's Avatar
    Join Date
    Feb 2005
    Location
    Oregon City, Oregon, USA
    Posts
    374
    The L94 certainly looks cooler! Appears they aren't completely interghangable, though:http://audioheritage.org/vbulletin/s...9&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.
    "Zobel is as zobel does"

  6. #6
    Senior Member Uncle Paul's Avatar
    Join Date
    Feb 2005
    Location
    Oregon City, Oregon, USA
    Posts
    374
    Tom, just read your post. That is a great idea!
    "Zobel is as zobel does"

  7. #7
    Senior Member
    Join Date
    Jul 2003
    Location
    Orange County, CA
    Posts
    2,140
    Quote Originally Posted by Uncle Paul

    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.

  8. #8
    Senior Member Uncle Paul's Avatar
    Join Date
    Feb 2005
    Location
    Oregon City, Oregon, USA
    Posts
    374
    Any idea who makes them and where to get them?
    "Zobel is as zobel does"

  9. #9
    Senior Member frank23's Avatar
    Join Date
    May 2005
    Location
    The Netherlands
    Posts
    337
    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

  10. #10
    Obsolete
    Join Date
    Apr 2003
    Location
    NLA
    Posts
    14,425

    4344 MKII lens

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

  11. #11
    Senior Member
    Join Date
    Jul 2003
    Location
    Orange County, CA
    Posts
    2,140
    Quote Originally Posted by Uncle Paul
    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).

  12. #12
    Senior Member
    Join Date
    Sep 2004
    Location
    MA
    Posts
    539

    2308 Lens

    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.

  13. #13
    Senior Member Ian Mackenzie's Avatar
    Join Date
    Apr 2003
    Location
    The Tardis
    Posts
    5,951
    Mike Caldwell used to have a stack of those.....some nos ...he might be able to source some more.

  14. #14
    Senior Member Uncle Paul's Avatar
    Join Date
    Feb 2005
    Location
    Oregon City, Oregon, USA
    Posts
    374

    Update

    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/obso...ns_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?
    1. Adds to the collective knowledgebase of the Forum
    2. Fairly simple first project I can use to give a little back for all the Forum has provided me.
    3. Will provide a way for Forum members who can't obtain the genuine article to make their own.
    4. Sooner or later it will become difficult to obtain the real deal. Old ones break every day, and none are being made.
    5. Variety: The DIY lens could be made of metal, plastic in any color or transparancy. The plates could even be veneered if desired.
    6. 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!).

    "Zobel is as zobel does"

  15. #15
    Super Moderator Hofmannhp's Avatar
    Join Date
    Dec 2003
    Location
    Central Germany
    Posts
    1,349

    2308, L91

    Quote Originally Posted by 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.
    ....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
    Please help us save more info about the vintage systems. Let us register your speakers and drivers.

+ Reply to Thread

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. CD versuc Wide dispersion lens
    By Bernard Wolf in forum Lansing Product General Information
    Replies: 1
    Last Post: 12-24-2003, 12:59 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts