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One of my 416-8B's fails to meet it's T/S parameters by quite a lot. The other in the pair is right on. This had it's cone replaced 10 years or so ago. I'm not currently using these drivers.
I am a little puzzled why a working woofer would be off so far, but it is the case.
I see a recone kit on ebay for a reasonable price. Being a die hard DIY guy, I wonder if I could replace a cone myself.
So 2 questions:
What is required?
And will it restore the T/S parameters?
No lectures on taking it to GPA please. I will do just that.....unless I can do it myself. I picture some sort of alignment tools for the voice coil in the gap.....and special glues.
Ron
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Reconing can be a DIY procedure but you should walk before you can run. Trying to match the T/S on another driver with your first recone, unproven kits, different glues and techniques will likely not occur. Get yourself a throw away driver and play with it...dismantle it...get a feeling for how it is put together. Then you will be ready to learn to recone.
No special tools are required. The VC is aligned in the VC gap by placing thin strips of cardboard all around it. Once the VC is centered and well positioned the spider and cone surround are glued and the rest is done. The details are too many to describe in this brief setting. But that was how I learned and I stopped counting how many I have reconed a long time ago.
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You'll find most of what you need to know here:
http://www.decware.com/surround.htm
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Reconing isn't too difficult, but does require special adhesives and a proper amount of skill to accomplish properly.
Now, with that said, let me say this - if your speaker has that new of a cone in it and doesn;t meet spec, then in all liklihood, the Alnico V magnet has lost some of it's "umph" and needs to be re-magnetized.
There is also a thin possibility that the unit has been dropped or damaged some other way, and has lost some power that way...
Remagnetization requires special equipment, but is performed FREE by Great Plains Audio when they recone, thus assuring that it is working properly when it leaves their shop.
Send it to Bill!
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Another question I would ask is was the re-cone kit an original ALTEC or a Waldom. During that time ALTEC kits were extremely expensive so many woofers during that time would have Waldom cones in them. The easiest way to tell would be to look at the series of numbers. Usually a Waldom will have a W to start the series of numbers off.
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Thanks for the insights guys.
I figured there would have to be some method to center the voice coil in the gap. And I figured there would have to be special goops and glues....that I don't have. I doubt they come in the cone kit.
I didn't look all that close at the kit I saw on Ebay, but it was a real Altec part.
As for magnet damage, I bought these woofers brand new in '77. They haven't been dropped.
Ant it is the one with the original cone that has gone out of spec, not the one that was reconed years ago.
Rather than expirement with this, I'll likely send it to Bill as he does excellent work.
I really just wondered how possible it was to do!
Thanks
Ron
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The kit shown is a 21554?
"Says" it s for a 416........
