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!
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Originally Posted by Kay Pirinha
I'm not sure of anyone in Germany who does it. Alternatively you could send them to him, won't be cheap though.
