Amplifier blowing

[XanderMoser 10+ year member]

WRONG...do not fuse to your amplifier rating, fuse to you wire size. the reason the fuses are on the amp is to protect the amp, the fuse is on the wire is to protect the wire. unless his amp requires an external fuse, there is no reason that he should have 100 amp fuse inline with the wire. unless thats the max amperage that his wire can handle, therefor he would need bigger wire.
what size wire are you running?

Yeah, I was just going to say that.

The fuse on the wire has nothing to do with the fuse sizes on the amp or why your amp fuses are blowing.

Is the sub a single voice coil? Sorry, I'm not particularly familiar with JL equipment. What impedance is it hooked up to on the amp, what RMS should the amp make at that impedance, and what RMS can the sub supposedly handle?

You'll get better performance from a ported enclosure. Try tuning to 34ish hz. Use an existing box and port design if you're not familiar with designing enclosures.

Turn off any bass boost, on the amp and HU and any bass boost processing between.

Do that stuff, now get back to us.