Converting 2402 to 2405

[cosmos]

I have several pair of 2402 and 2402H sitting on the shelf... I will be selling some off in the future, but I would also like to use a few pair for higher end projects planned..

Is there a economical way to convert 2402 or 2402H over to 2405(H)?

Is there a better front end for them? Something out of wood, perhaps?

[Mr. Widget]

Is there a better front end for them? Something out of wood, perhaps?I've never seen that, however you could get a 2405 and carefully copy the center wedge and horn in wood... actually using an acrylic wedge à la the 077 and a nice walnut horn combo would look pretty damned cool... hell, you could even tell people how much better it sounded than stock and I bet some folks would even believe it. ;)


Widget

[spkrman57]

But I'll be watching your progress on this endeavor!

Regards, Ron



I have several pair of 2402 and 2402H sitting on the shelf... I will be selling some off in the future, but I would also like to use a few pair for higher end projects planned..

Is there a economical way to convert 2402 or 2402H over to 2405(H)?

Is there a better front end for them? Something out of wood, perhaps?

[tomee]

the amazing work of John W of course...:applaud:

http://audioheritage.org/vbulletin/showthread.php?t=5951&highlight=3-way

[Earl K]

Hi Cosmo,


- Okay, it's not exactly what you asked for but ; ( & because I'm such a big fan of Johns' work / ,,,oh,,, I see tomee beat me to the punch )

- Here's what John W did when he modified the bell section of his 076s ( into something more like a TAD 703 ) .

- The orginal thread (http://www.audioheritage.org/vbulletin/showthread.php?p=62755&highlight=076#post62755) for the source of these images .

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=8959&stc=1&d=1121438770http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=7798&stc=1&d=1116701149

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=8430&stc=1&d=1118715124http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=8429&stc=1&d=1118715114
http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=8432&stc=1&d=1118715164http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=10564&stc=1&d=1129771623



http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=10565&stc=1&d=1129771629

>< cheers ;)

[toddalin]

I have several pair of 2402 and 2402H sitting on the shelf... I will be selling some off in the future, but I would also like to use a few pair for higher end projects planned..

Is there a economical way to convert 2402 or 2402H over to 2405(H)?

Is there a better front end for them? Something out of wood, perhaps?

You can put a 2405 diaphram in a 2402 to greatly extend the top end response and smooth the overall response above ~7K. It will not be a 2405, but will be a far cry nicer than the stock 2402 if you are crossing them over above 7kHz. You may or may not need a shim to keep the 2405 diaphram from touching the 2402 phase plug. I made my own shims to do this and they are documented on another site.

If you want to put an elastomeric ring filter on the 2402 with a 2405 diaphram, you can get the high end even smoother and more extended than a 2405 between 10-20 kHz, with greater dispersion in the vertical plane than the 2405, but you are going to have to go to a different web site to see the work I did on this aspect.

Economical..., well, no real JBL diaphram is economical.

[tomee]

.... I see tomee beat me to the punch...

<snip> ..
>< cheers ;)

but your post is better! I saw the question and knew exactly where to go because I've bookmarked every one of his projects - they are all amazing to see!

An idea struck me later - what about a turned bullet horn but with a conical section, or something that might make it more 'constant directivity' like? That's getting into 'engineering' vs. a parts swap, but still interesting...

[cosmos]

Dang, you guys know how to load up a guy with ideas and that woodworking is beautiful!

I Think I need to sharpen my tools and fire up the lathe... and locate some 2405 diaphragms.

I think I know the answer, but is there a different 2405 diaphragm for a 2402 from a 2402H? I have both Alnicos and Ferrites to draw from.

[cosmos]

Do 2402 (alnico) and 2402H (ferrite) come from JBL with the same diaphragm?

[4313B]

Here's the ring radiator matrix I posted in another thread many years ago -


http://audioheritage.org/vbulletin/attachment.php?attachmentid=913&stc=1&d=1063884846

Additionally:


All three diaphragm kits D8R075, D8R076, and D16R2405 use the same voice coil part number.



Both D16R2405 and D8R075 use the same diaphragm part number. D8R076 uses a different diaphragm (dimensions).



All three kits use the same raw diaphragm material (.002 inch thick Aluminum).



There are also some differences on the diaphragm spacer rings used in each kit.



Since this product has been built since the late 50’s there have been many variations. Basically there is only 1 diaphragm (2 mil aluminum) one coil impedance and a variety of clamp ring diameters. For a while, we did have a 1.6 mil diaphragm but I think those are long gone. There is a clamping ring on the interior and exterior of the diaphragm. This ring comes in silver and blue. The blue ones have different ID’s and OD’s than the silver ones. The differences in the diaphragm assemblies come from whether the assembly has 2 silver, or 2 blue or a mix of silver and blue rings. This changes the clamping diameters and thus the stiffness of the diaphragm. Over the years, things have changed with the aluminum and the way the diaphragms are creased at their outer edge. This led to the different rings.


To my knowledge, all of the motor assemblies are interchangeable from a mechanical standpoint. The ferrites probably have a little more flux level than the alnico’s but that is all. The main difference in them is the horn or bullet or whatever is mounted on the front side. Any diaphragm can go in any body. Results will vary.

2402 2403 2404 2405 075 076 077