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View Full Version : JBL 4430 - 2421, diaph alu or titane and upgrades



ougo
12-01-2008, 09:15 AM
Hello,

I am the happy owner of JBL 4430 since last week. I use it with an unison research S8 (845 SET from italy), results are quite good and it give a lot of pleasure. So i think that they will stay at home.


These 4430 are first series ones, the mid voice is a 2421 (probably "a" but i need to check) and i think that a pair of new diaphragms can be a good investment.
What do you think about that?
I saw that it was possible to use diaphragm from 2425 or 2426, but i also saw that some people prefer aluminium to titane. How is it possible to describe the sound of both solutions?
Where is it possible to buy new diaphragms (which price)?

And concerning the alnico 2421? Do i need to do something?


At least, the network's components are probably old and modern ones could be better choice (as for capacitor). Do someone has some experience in this area?


Thanks for all.

Ugo (from France)

Robh3606
12-01-2008, 09:52 AM
And concerning the alnico 2421? Do i need to do something?


Hello Ugo

Probably not. If you are getting good HF extension out beyond 10K like you should I would not worry about it. Chances are they are fine as is. Have a look at this it may take care of an De-Mag fears with these drivers.

http://www.audioheritage.org/vbulletin/showthread.php?p=177175#post177175


i think that a pair of new diaphragms can be a good investment.
What do you think about that?

That's a good idea depending on how old they are and how hard they were pushed. Do you know if these are the originals?? Aluminum does fatigue and frankly diaphram prices have done nothing but increase in cost. Replacements in aluminum are not inexpensive. If you go Titanium even as spares I would have them coated with Aquaplas. Aquaplas coated titanium diaphrams on those horns sound very good.


the network's components are probably old and modern ones could be better choice (as for capacitor).

You could upgrade the mylars and electrolytics to PP caps and you may want to consider doing Charge Coupled networks for them. In have been using the combination of CC networks and Coated diaphrams for a couple years now and to me it's really sweet sounding combination.

http://www.audioheritage.org/vbulletin/showthread.php?t=3555

In any case enjoy them and welcome to the forum.

Rob:)

ougo
12-02-2008, 11:05 AM
Hello Rob,

Thanks a lot for your answer.


That's a good idea depending on how old they are and how hard they were pushed. Do you know if these are the originals?? Aluminum does fatigue and frankly diaphram prices have done nothing but increase in cost. Replacements in aluminum are not inexpensive. If you go Titanium even as spares I would have them coated with Aquaplas. Aquaplas coated titanium diaphrams on those horns sound very good.

I search place to buy an original D8R2421 and i discovered that it's quite expensive. By comparison the D8R2425 is cheap.
I found a thread on Aquaplas... what is it? Do you know if someone has some D8R2425 aquaplaced to sale? It can be a good solution.





You could upgrade the mylars and electrolytics to PP caps and you may want to consider doing Charge Coupled networks for them. In have been using the combination of CC networks and Coated diaphrams for a couple years now and to me it's really sweet sounding combination.

http://www.audioheritage.org/vbulletin/showthread.php?t=3555

In any case enjoy them and welcome to the forum.

Rob:)

Ok, it seems to be a good idea too. I will search on the forum 4430 schematic crossover.
Does someone try to change capacitors by paper in oil ones? As audio note cooper for exemple?
It's just that by experience, audio note cooper paper in oil has a very nice and liquid mid and upper range.


Thanks

Ugo

ougo
12-02-2008, 11:24 AM
I found new threads on aquaplas and discover step by step what it is.

Ugo

pos
12-02-2008, 11:54 AM
Hi ougo
Maybe you can contact member Guido. He is in Germany and might sell you some diaphragms and aquaplas them for you.
I send him my 2435 for cleaning and aquaplassing and he did a great job :)

ougo
12-02-2008, 01:48 PM
Hi ougo
Maybe you can contact member Guido. He is in Germany and might sell you some diaphragms and aquaplas them for you.
I send him my 2435 for cleaning and aquaplassing and he did a great job :)

Great, good idea, i will send him an email.
How could you describe the before and after aquaplas(hing)?
Thanks

Ugo