JBL 2202A with 15" basket! - what to re-cone as?

[Mazza]

Dear all,
I have stumbled upon a franken 2202A that has been fitted with a 15" basket. The seller is a reputable local speaker repair outfit. The unit is free, I just need to re-cone it.

I'm thinking of re-coning as a 2235 as the 2202A's 4" voice coil gap will accommodate the recone kit for that driver.

I'd like to use this woofer in a potential rebuild of some 4331's (http://www.audioheritage.org/vbulletin/showthread.php?43069-JBL-4331-rebuild-using-2445J-and-JBL-woofer-would-this-be-a-good-idea-Help-pls!).

I've read around the site about franken recones and dug up the following chart - What this misses is the 12" to 15" interchangeability.

Any suggestions are welcome!

Cheers.


89763



89764

[jbl4ever]

Hello Mazza, the magnet assembly looks correct but the basket does not look like it is a JBL frame. Can be a problem if not for the depth of the recone kit

[Mazza]

G'day jbl4ever,
The recone kit I'll be using is in parts so I can accommodate a different depth frame, to some extent.
I'll ask the shop to confirm that their kit will fit the frame depth. Hadn't thought of that actually!
Thanks heaps for your input.
:)
Cheers.

[Earl K]

Hi Mazza,

It seems to me that you've stated that this frankensteen setup is free to you as long as you pay full retail for a recone at the reconers shop.

I'd say pass.

There are multiple issues with that non-JBL frame.

One serious issue is how the frame lip appears to still be present under the area of the cone-kits surround ( this area is left open for movement in a bona-fide JBL basket ).

I see an @ 3/4" extra lip that will impact any surround that's placed above it.

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=89764

That can't be fixed in the mix ( so-to-speak ).

:)

EDIT:

Here's what a bona-fide JBL basket looks like ( note the frame edge which is only wide enough to glue down the cone kit edge ).

[Mazza]

As always EarlK THANK YOU! So generous with your time and knowledge. :applaud: :bouncy:



As luck would have it I received my four brand-new-secondhand woofers (http://www.audioheritage.org/vbulletin/showthread.php?43069-JBL-4331-rebuild-using-2445J-and-JBL-woofer-would-this-be-a-good-idea-Help-pls!&p=438623&viewfull=1#post438623) today and was gifted a somewhat damaged extra E130-8 into the deal...


89768


Dropping a woofer does indeed seem quite detrimental!

Is it possible to re-centre the pole piece? It's crushed the VC so hard I couldn't get it out! :eek:


89771


I'm going to get a local specialist metalworking shop to try and straighten and weld the basket. Perhaps the 2202A can fit this 15" unit???

I'm not giving up on my franken 2235's!

:cheers:

[Earl K]

Mazza,

My embryonic thoughts on how to fix // re-center a woofers top-plate are found within This Thread! (http://www.audioheritage.org/vbulletin/showthread.php?42996-Altec-GPA-515-LF-16-ohm-new-magnet&p=438208&highlight=#post438208)

The bare essentials are that one needs to look to the automotive industry for help // inspiration // specialty-tools // etc.

:)

PS;

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=89439&stc=1&d=1629407687http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=16911&stc=1&d=1153262338http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=16909&stc=1&d=1153262280

[Woofer]

OK. I hope you can make sense of this...

One way of re-centering a pole piece without having to demagnetise, is to stick a credit card down the opposing gap, make sure it's exactly opposite the 'non-gap', and then place a piece of wood against the magnet of that side with the credit card, and give it a good whack with a hammer. The pole piece will try to move over to the impacted side, but can't because of the card. I forgot to mention, credit cards are the exact right size for the gap.. Then just grab the card firmly and pull it out. You might have to wriggle it.
Try it. You got nothing to lose. Done it lots. It works.
btw, this is not the sort of thing you should be doing to magnets, but the wood block minimises the shock when belted with a hammer. Too much physics to explain [Netwon's Law of Motion etc.] for a one finger typist at 2 in the morning.....
Once you're absolutely sure it's centred, attach a long syringe needle to a tube of super glue, and squirt heaps as far down as you can get it. Give the whole speaker a bit of a 'swish' [like you're panning for gold], before it sets to try and let it find it's own way around the bottom of the pole piece. Make sure you get it nowhere near the gap.
Anyway, this is an old family secret passed down for generations. Please don't tell anybody.

[Mazza]

Thanks heaps woofer. I'll give it a try :thmbsup:

[Woofer]

Thanks heaps woofer. I'll give it a try :thmbsup:

Warning: If you break the hammer, you're hitting too hard. Best of luck Mazza. Let us know how you go. :)

[short_circutz2]

[SIZE=3]

I'm going to get a local specialist metalworking shop to try and straighten and weld the basket. Perhaps the 2202A can fit this 15" unit???

I'm not giving up on my franken 2235's!

:cheers:

I dont understand why you're trying to install a recone kit for a 12" speaker into a 15" frame...

[grumpy]

Thinking it's just talk about the magnet from a 12" 2202 ... Putting that on a curious 15" frame and then expecting sound would come out of it.
Seems like a lot of effort unless the recone parts are nearly free and the point is to gain some learning experience in speaker assembly... but I'm not paying a lot of attention.

[Mazza]

Gent's thanks for your comments. And I do understand your perspective.

The primary reason I'm interested in this mash up at all is because of just how rare a driver with the parameters of the 2235 is.

The mix of efficiency, bass extension, xmax and low inductance in a 15" is difficult if not impossible to match.

I'm just not aware of any other driver available today that compares unless we get into AE price territory. I remain eternally open to being corrected here - please do send me your suggestions!

Drivers like this are very expensive in Australia; partly due to currency exchange and that shipping can cost as much as the driver itself. Therefore the economics of purchasing a large and heavy driver like this from overseas is very very different to what a continental US or European builder might face where free or very low cost shipping seems the norm.

The other part of this for me is the learning. I have the DATS measuring gear necessary to actually verify the parameters of the mashed up driver and therefore make the best use of it. I have built several systems from parts as I also have Omnimic so am not too concerned what I end up will become shelf-ware.

Finally, I relish the satisfaction of turning what others might send to landfill into something that brings me or others some musical joy into their lives. Recently I built a pair of Econowave (https://www.stereonet.com/forums/topic/332792-marantzowave-econowave-2-way-build-using-locally-available-parts/) inspired floor standing speakers for my niece's birthday present (that are now in her first share house) from parts that were literally destined for the dump. She's delighted with the result and for me that's what its all about.

My goal with my 4331 restoration project (http://www.audioheritage.org/vbulletin/showthread.php?43069-JBL-4331-rebuild-using-2445J-and-JBL-woofer-would-this-be-a-good-idea-Help-pls!) is the same, so your inputs are very much appreciated.

:cheers:

[grumpy]

I appreciate your moxie.
:cheers:

[Mazza]

Thanks heaps grumpy! :applaud:

So the speaker repair mob has provided me the following pics with a 2235 spider and cone on the franken 2202A, thoughts?....


89788



89789



Looks good to me :bouncy: Yes???

[Woofer]

As long as the voice coil lines up in the gap of that top plate you should be good.
How did you go with fixing the pole piece?

[Mazza]

G'day woofer,
Thanks for your feedback :thmbsup:

Haven't had time to have a bash at the E130 motor.

Will report back when I do.

Cheers.

[DogBox]

G'day woofer,
Thanks for your feedback :thmbsup:

Haven't had time to have a bash at the E130 motor.

Will report back when I do.

Cheers.

Hi Mazza,

Did you think to try and find some JBL 2225 frames for your 2235 reconing venture? I might know where to find some...? :blink:

Kind Regards,
DogBox
[steve]

...

[Mazza]

Hi Dogbox!

Well yes, I have looked long and wide for 2235's and any frames that might be a base for a pair.

Please do tell if you know..... :D

[Woofer]

Hi Dogbox!

Well yes, I have looked long and wide for 2235's and any frames that might be a base for a pair.

Please do tell if you know..... :D

I've PM'ed you.:)