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

[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/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.

[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?

[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

[John W]

Has anyone gotten anywhere making their own copy of these?

[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/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!).