How does fuse size help you determine the rms output?

[Ahmed Johnson]

I see alot of people on this site rating an amp by the fuse it needs. The reason I ask this is because if an amp is 1000 rms with an 80-100 fuse rating, won't the bass boost when used, blow the fuse every time? Or does the amp not get anywhere near rated without the bass boost? I don't have a specific amp in mind, and I'm cool with the ones I got now. I just want to get a better perspective on the subject.

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[trumpet 5,000+ posts]

I don't believe in judging an amplifier based on the internal fusing, although as a very rough ballpark guesstimate it can show you if power ratings are likely to be way off. The rule of thumb is 10 amps per 100 watts, so a 1,000W RMS amp should have 100 amps of fusing. Amplifiers don't use fast blow fuses, so they can pull more current than the sum of the internal fusing without blowing the fuses. An amp should NEVER blow its fuses during normal operation. Fuses are there to prevent catastrophic failure.

 

[Ahmed Johnson]

Thanks. But even with a stronger fuse, won't the bass boost blow the fuse immediately? I mean, if the amp is putting out the max rms, won't the bass boost push that rating higher on certain hz?

I don't believe in judging an amplifier based on the internal fusing, although as a very rough ballpark guesstimate it can show you if power ratings are likely to be way off. The rule of thumb is 10 amps per 100 watts, so a 1,000W RMS amp should have 100 amps of fusing. Amplifiers don't use fast blow fuses, so they can pull more current than the sum of the internal fusing without blowing the fuses. An amp should NEVER blow its fuses during normal operation. Fuses are there to prevent catastrophic failure.

 

[trumpet 5,000+ posts]

Thanks. But even with a stronger fuse, won't the bass boost blow the fuse immediately? I mean, if the amp is putting out the max rms, won't the bass boost push that rating higher on certain hz?

Once again, the fuses do not blow instantly once the rating is exceeded. Bass boost is a single band of EQ, not an instant fuse killer knob. This all is based on the constantly changing input of music. That all goes out the window with SPL testing, in which case you would not be using bass boost.