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budney
03-24-2020, 08:58 AM
I've recently come into possession of a number of alnico 15 inch drivers. 2220A, 2220B, 2205B, 2231A, 2 x K145, 2 x LE15.
All have been reconed incorrectly. One K145 looks to be a 2220 kit perhaps, curvilinear cone. The other is an empty basket. The LE15s look correct but the back of the cones have 2235 written so I assume someone has reconed incorrectly. The others have E140 kits in, which I will extract to be used in some E140 baskets. I now plan on getting these all back to proper stock kits.

I've found someone in the UK who has a regaussing machine so thankfully they can all get recharged back to the proper magnetic strength. However, there is now the problem of the correct recone kits. All these kits are NLA, so I have to resort to aftermarket. I have had good experience with aftermarket kits currently on the market. I know Edgewound (Upland Loudspeaker) has used aftermarket voice coils with good results, however thats only with ones that are produced correctly, E series, 2202 2225 etc.

As far as I know, the underhung series, K145, LE15, 2220 were originally with small copper voice coils. The only aftermarket coils on the market available for them are aluminium. I have reconed another pair of LE15 I have with some of these aluminium voice coils and they sound good, but I know they aren't as good as the originals were.

Now comes the good news, the person I have found to do the regaussing also has an edge wound coil winding machine! He used to do a lot of work for Martin audio, Turbosound back in the day so he is very qualified to produce some new in spec JBL voice coils for me. However, what we do not have is that spec!

We need the number of turns, voice coil depth, etc etc, all the specifications required to reproduce these voice coils. This is where I need some help. Is there anyone on this forum that has this info, and would be happy to assist me in bringing these drivers back to life? I do have a dead LE15B cone kit I removed, so we could measure the voice coil from that. My regausser guy also has a 2215, he could extract the kit to measure the coil, but we would like to be as informed as we can be with this project. If anyone has any info to share I would really appreciate it.

My plan is to recone the 2220, K145 and LE15 back to stock. Then I was thinking if the 2235 kits that are currently in the LE15 are still good, I could remove them and transplant into the 2205 and 2231, then I would have a pair of nice alnico 2235.

If I come up short I could always use the aluminium coils on the market, however I would like to avoid that if possible!

FE3T
03-24-2020, 11:32 AM
I cant help with specs for your coils.
But i would love to get in touch with this guy since i need som coils
not aviable anywhere myself.

Kay Pirinha
03-25-2020, 03:11 AM
Sorry, I also can't help with VC specs, but am interested to get in touch with anyone who's able to regauss those AlNiCo-V magnets to their original strength.

I have a question, too: How does one extract a complete cone assembly without damaging it?

Best regards!

budney
03-25-2020, 03:36 PM
Sorry, I also can't help with VC specs, but am interested to get in touch with anyone who's able to regauss those AlNiCo-V magnets to their original strength.

I have a question, too: How does one extract a complete cone assembly without damaging it?

Best regards!

There are a couple of people in the UK who can do it, but the person I've found is by far the most likeable and friendly :) I'm not sure of anyone in Germany who does it. Alternatively you could send them to him, won't be cheap though.

In terms of extracting a cone, since they are recones, I don't think the glue will be as 'cured' as they were be if they were from the factory. So I'm hoping a generous amount of MEK will help. If that doesn't work then I'm sure he has a few industry secrets up his sleeve to be able to do it. Perhaps we would have to remove the surround and spider, then install some new suspensions. With the 2235 the foam has gone so that will be relatively easy to remove from the frame in one piece. Some MEK and a very sharp scalpel under the spider.


I cant help with specs for your coils.
But i would love to get in touch with this guy since i need som coils
not aviable anywhere myself.

If we succeed I would be more than happy to share :) but we need to get the spec first!

Kay Pirinha
03-26-2020, 12:20 AM
Thanks budney!

I hadn't realized that the glue that fixes the surround and the spider to the basket is soluble.

Anyway, if we'd try to extract an intact 2235H cone or any other one with foam surrounds I guess that the surrounds gets damaged by the solvent?

Best regards!

FE3T
03-29-2020, 02:30 PM
If we succeed I would be more than happy to share :) but we need to get the spec first!

What i need are coils for the 2108H and 2122H.
Those specs are already aviable on this site.

The specs you need are sadly enough, not.

What i dont have are someone to wind them, without forcing me too pay for hundreds of them.

rogerjulien
03-31-2020, 07:08 AM
Hello,

I would also be interested in some Edgewound VC by original specs for 2122, four at least.

thanks

budney
03-31-2020, 08:58 AM
everyone has to get in line :D the LE15/K145 coils are coming first! He hasn't used his coil winder for a number of years so he's currently working on restoring it in his spare time. But unless we find the specs for these coils I think we wont be getting any coils made at all!

I found this, which seems the only available info on this website with regards to the specifications of the voice coils. I hope this, along with some measurements of fried coils and the specs of the aluminium ones online, will be enough for us to get some made again.
86153

ompdiburi
03-31-2020, 09:24 AM
I have an original C8RLE15B kit, I can take some measurement from that, if helps, let me know.
Giuliano

FE3T
04-01-2020, 04:03 PM
But unless we find the specs for these coils I think we wont be getting any coils made at all!

Please claryfi, does this mean that unless you get what you need, you are not going to forward any requests or share any contact info?
Or is it the guy with the winding machine who refuses any other business unless he can help you out?

Flodstroem
04-16-2020, 05:39 PM
Just measured a 2215H coil. It was 7.8-7.9 mm long. DCR was approx 5.8 ohms (8 ohm coil)
Wander if it should have been 0.29 inch long, same as the E-145 etc...
A 2220 coil has the same length though it is a 16 ohms coil.
Could possibly count the turns tomorrow with a magnifier..............

Kay Pirinha
04-17-2020, 01:41 AM
Are JBL's voice coils wound single or double layered?

Best regards!

Flodstroem
04-17-2020, 05:49 AM
Are JBL's voice coils wound single or double layered?

Best regards!

I have newer seen a double layered JBL voice coil. All of those I have seen (from about 1972) was/are single layered.

Flodstroem
04-17-2020, 06:06 AM
If we succeed I would be more than happy to share :) but we need to get the spec first!

Have count the turns for 2215H, 2220A and the LE8T voice coils:

2215H = 63T, 7.8 mm in length (Cu wire 8 ohms, DCR 5,8 ohms)
2220A = 100T 7.8 mm in length (Cu wire 16 ohms, DCR 14.2 ohms)
LE8T = 38T, 3.8 mm in length (8 ohms, Al wire)

I think JBL also used the 2220A voice coils for the LE15A, or vice verse because they measure the same physical dimension and DCR. :)

Earl K
04-17-2020, 07:24 AM
Thanks Flodstroem for taking the time to do that.

That's good info!

:)

Flodstroem
04-17-2020, 08:18 AM
Thanks Flodstroem for taking the time to do that.

That's good info!

:)

Thanks Earl K, :)
If I had other JBL voice coils I could have checked those too. But usually I dont keep hold on those broken cones when I re-cone speakers. Now that was a drawback in this case :(
I have LE14H-1 but that is an over hung voice coil.

Kay Pirinha
04-17-2020, 01:02 PM
I have newer seen a double layered JBL voice coil. All of those I have seen (from about 1972) was/are single layered.

Thanks, Flodstroem ;)! How is the VC end that is far from the cone terminated then, i.e. connected to the tinsel lead?

Best regards!

Flodstroem
04-17-2020, 04:40 PM
Thanks, Flodstroem ;)! How is the VC end that is far from the cone terminated then, i.e. connected to the tinsel lead?

Best regards!

The VC wire that is most far from the cone is turned flat inside the coil formers to ends/joint and glued to the VC. The wire is ribbon wire and thats the reason why this could be done, see the picture.