Actually we don't use a fuse, but rather a High Positive Current Coefficient Resistor (HPCCR). Unlike a fuse, as the HPCCR gets hotter and hotter its resistance goes up at a very fast non-linear rate. A fuse does not change its resistance very much until it reaches its burn out current. We use the HPCCR to compress the current level to the tweeter and high pass section of the crossovers to protect them. A standard fuse will not add this compression and you will likely experience tweeter failure.