Which coil? Pondering old sub rebuild.

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Deiimos

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So I’m considering rebuilding an old sub that has been blown for some years now. Looks like I "should" be able to squeeze in an 8 layer flat wound aluminum, or I can go with a 4 layer round copper wound. Any opinions on either coil? That's the basic question. Just using it for basic everyday music.

Talking about an old Kove Armageddon 15, uses a 3” coil. After dissection, it appears to have a 4 layer round aluminum wound coil originally.

Have had this sub sitting dead for quite some time, so no real rush to rebuild it, just thought I'd create a thread on the voice coils.


Optional read below this point, has nothing to do with question, but since I don't post much.
My original plan was to find a matching motor / basket to build up a pair of 15's, so been waiting to rebuild this, but these exact Kove’s don’t come up very often, this is the Z series Armageddon, and when I have seen them on ebay, they were insanely priced for what they are, or the font on the motor wasn't exact and didn't pull the trigger thinking the motors may not be exactly the same, and I don't want two mixed matched motors. So, thinking of just rebuilding it as I still have the box I built for it.


It's pretty old now, and has lived a rough life, even before I got it.
A part of me is tempted to just buy a coil for it to be cheap (4 layer copper coil since it is cheaper) and use old soft parts (originally what I was thinking, just revive it on the cheap, and I'm fairly confident I can get the old coil out without trashing the cone / spiders, and put a new one in), didn’t really want to dump a ton of money into this old sub, even though I liked it and it is a decent motor. But should probably do all new soft parts. Either route is still cheaper than a new equivalent sub. Hmm… At any rate, was curious about the two possible coil options.

Don’t really need to add any photos, but will because why not?
After careful dissection. (I grew up taking speakers apart to fix broken voice coil leads, so have experience not totally destroying the soft parts, but the dust cap was e6000 glued on 10 years back and was not letting go, so did rip the paper cone a little)

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Talking about an old Kove Armageddon 15,
Nice! I have that exact model series but in 12" format. Also was looking in ebay for a partner for it but they were always $600+. Now there is not a single one. I think I'll pull it out and run it a couple if months, see how it handles.
As for rebuilding, I have no experience. But I do want to try it on a pair of old Fosgate 10s with sagging spiders.
How did you separate the surround from the frame?
 
Nice! I have that exact model series but in 12" format. Also was looking in ebay for a partner for it but they were always $600+. Now there is not a single one. I think I'll pull it out and run it a couple if months, see how it handles.
As for rebuilding, I have no experience. But I do want to try it on a pair of old Fosgate 10s with sagging spiders.
How did you separate the surround from the frame?

That's what I seen looking for Kove's, crazy prices, and now don't see any, not that I would pay those prices anyway. Not easy to find a match for one, that's for sure!

I picked up a 12” Kove a few years back, only model I could find that looked like it was M series Armageddon, but it’s tiny compared to the Z series, and only a 2" coil. I’ll add a pic of that one below.



As for separating the surround, as well as spider without damage. This won’t really work for hard brittle style super glue, although, it might help, mainly only a rubbery adhesive, which most factory made subs use. And only works on steel or aluminum baskets. A small mini torch with a fine flame (I have a Power Probe butane soldering kit I use as just a torch with no tips on it). Remove the rubber gasket ring if it has one, and heat the basket under the surround with the flame. You’re not trying to make it glow red, you keep the focused flame moving to heat a section between screw holes to soften the glue, then use a flat head screw driver to slip under the surround while it's hot and gently scrape under it lifting the surround. If it isn’t coming up easy, add a little more heat. Just to make it clear, you're heating the metal frame under the surround, the flame never touches the surround or cone, or spider. You won't burn the surround if you're careful, just the glue in between it and the basket. I’d suggest practicing on an old subwoofer / speaker first that is junk if you have one. You might be able to use a hair dryer, or heat gun, but the heat isn't focused enough and would take forever if even possible (heat gun gets hot enough, but risk burning the cone and surround). I did a bunch of speakers / subs, so you get a feel for it to not burn anything, even did a few cheap coaxials that had debris in the gap :LOL:. Same thing for the spider, although sometimes this may not be easily possible depending on basket design (remove rubber magnet boot if close to the spider landing, and don’t get the magnet slugs hot). I made a video on this process 10 years back demonstrating on a different sub, but video has been gone for a long time, suppose I could do another at some point. It won't work on everything, but I've been able to get quite a few apart like this over the years.


Here’s the Kove 12 I have next to the Z 15, removed the soft parts on that one like this as well, most of the surround glue came right up with the surround. This one had a broken basket I had to rig up. Worked good until the motor fell off in the box from old dried up glue. :ROFLMAO: I've yet to try and glue the top plate back on.

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It’s most likely 8” spiders and with that motor I would stick to a 4 layer coil at a maximum of a 2” winding height. I’d rebuild it all fresh, not worth saving all the parts. It would be best to measure the factory coil using a set of calipers if you are having trouble measuring the top plate opening. This will give you an idea of what will fit. If it was mine, I’d unbolt the frame and get rid of the screws and upgrade to studs or socket cap screws. Would add spacers between the frame and motor for better cooling and would carefully sand down the top and bottom plate. Then I’d paint both plates and that thing would be basically brand new when all done.
 
I will add, I'm leaning towards the 4 layer, but not dead set on anything yet, and will be a little while before I actually buy anything.
I've rebuilt a couple of these myself with 4 layer copper as I recall. Really no telling how much performance will vary with a new coil and softparts but on something with a motor that big it should perform well enough so long as you fill the gap with coil, have enough space that it won't rub, and add stiff enough suspension that you won't break it mechanically with whatever power you're trying to run.

I definitely wouldn't be trying to save almost 20 year old softparts, they don't owe you anything at this point and I'd guess the tinsels or surround will be weak links going forward. As you say that plus all new softparts is probably going to do you better than anything you could get elsewhere for the cost of the soft parts.

If you're going through all the trouble you may as well try to buff up that motor to a nice shine either. Obviously super fine sandpaper as needed then rubbing compound and a wool buffing wheel then move on to hand rubbing to finish it'll probably polish up nice.
 
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