Just as rule of thumb always match the fuse under the hood to the amount of fuses in the amp. Technically speaking tho the 80 amp fuse will work with an amplifier than can draw up to 160 amperes of current, the reason for this is because a fuse will only blow if there is a direct short or you have drawn more than twice the rated amperage across the fuse example 80 amps x2 = 160 . There is also another factor that could make any fuse fail pre maturely and that is heat can cause some types of fuses to become weak..... anl fuses usually aren't affected by heat and thats why they're the most dependable under the hood. Hope this helps....