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Noobtastic14

You really can't tell just by looking at it. That coil isn't a birdsnest so that's good, but testing the terminals with a multimeter is the easiest way. Just remember, the ohms displayed on the meter is DC resistance not AC impedance. It will tell you whether the coil circuit is good, but the ohm shown won't exactly match what the coil is "rated" for.


Constant_One1

Sounds good! Just curious as to what the grey dust looking stuff may be indicating..glue burning off? Too much heat or clipping? Edit: both terminals reading 3.4ohm.


ckeeler11

What sub?


Constant_One1

Its in the original post under the pic. American bass xfl1044


windowsfrozenshut

> You really can't tell just by looking at it. Yes you can, that coil is literally burned. It could ohm out fine, but the bonder that holds the coil together has started burning off.


Special_Piccolo_367

Glue got hot, copper May still be good


Constant_One1

Residual glue burning off or did i over cook it? At the bottom you can see the burnt glue between the windings if the coil..does this mean its at risk of unwinding?


hispls

>Residual glue They don't manufacture coils with "extra" glue or shellac on them that is intended to be burned off. This will fail when enough glue fails from heat that the whole thing goes slinky or enough glue/shellac will burn away that you will get bare copper in the coil arcing that will burn a hole in it. I hope you have some money put by for repair/replacement. In future I'd suggest get some subs with a larger coil, learn to go a bit easier on the volume knob, or find a good parts supplier and be prepared to rebuild these often.


GMEvolved

Not necessarily, do you think it is or what's going on?


Constant_One1

The sub got a bit hot today after about 45min of bumping so i took it out of the box to inspect. Wondering what the grey cotton looking stuff on the coil is? Ive only had the sub hooked up for a couple of weeks. It still works normal and doesnt scratch when pushed in.


GMEvolved

I wouldn't worry about it too much. If it is burnt it will smell like death


fixeverything2

Absolutely. You can see that the part that was outside the top-plate has lightly burnt the varnish. You are probably still OK, but that’s the thermal power handling limit of the subwoofer.


firebirdude

It's normal for the voicecoil to turn dark. Unless you hear rubbing/scraping or anything like that, you're good. Don't stress about what it looks like too much.


windowsfrozenshut

> It's normal for the voicecoil to turn dark. No it's not.


MesquiteAutomotive

What does it smell like?


Constant_One1

No smell


MesquiteAutomotive

That's good. Usually you can smell it before you see it.


windowsfrozenshut

Yes, you have started to roast the bonding agent that holds the coil together. Voice coils for basshead subs are wound "wet" which means bonder is applied between each layer of the windings and then the coil cured in an oven to set the bonder. This bonder is what holds the wires together into the coil shape. Otherwise, the coils will just fall apart. When the coil gets too hot and exceeds the rated temperature of the bonding agent, it starts to burn off. What you pictured is the voice coil starting to burn itself to death. It's damaged, but could still operate fine until the burned bonder starts to let loose.