can fuse rating determine power output

[Tim]

This dude I know told me that an easy way to tell what kind of power an amp will put out is to take the ratings of the fuse(s) and add a zero to them.
Is there any truth to this??

for instance an amp with 2 50 amp fuses would be 50+50=100 add a zero to get 1,000.

Are fuses usually rated at a 10th of the amp power.


Is this a totally ignorant question?

Tim

[Ryan from Ohio]

That guys a turd.

A X V=Power as always. Take that formula and rearrange it as needed.

So 100 (fuses) X 13.8 (voltage)= 1380watts RMS.

[Tim]

That makes much more sense.

So you need to know what voltage that the amp is rated at, whether it would be 14.4 13.8 or what ever the case may be. Is that correct??

So after you know the voltage you just multiply the fuse value(s) by the given voltage, right?

Pardon my ignorance I'm very tired and not real good with formulae.

Tim

[Ryan from Ohio]

Nope.

Voltage is something determined by the alternator. If you got huge draws it can dip (aka voltage sag).

I just always figure off a constant/strong 12V rail @ 13.8 volts. Cars charge anywhere from 13.6-14.8 Volts Ive seen. I just use 13.8 because msot cars Ive dealt with measure that.

Then you toss in the fuses on the amp. If theres no fuses you run the formula based off the manufacturers specs.

[smoker]

its more a good indication of an approximation of what kind of power might be possible in a perfect world..but given that formula some amps make more power than they should.

[Tim]

Nope.
Voltage is something determined by the alternator. If you got huge draws it can dip (aka voltage sag).
I just always figure off a constant/strong 12V rail @ 13.8 volts. Cars charge anywhere from 13.6-14.8 Volts Ive seen. I just use 13.8 because msot cars Ive dealt with measure that.
Then you toss in the fuses on the amp. If theres no fuses you run the formula based off the manufacturers specs.

So you use 13.8 as a happy medium?? I can understand that. It actually makes more sense. Given that formula a 1500 watt amp with a 100 amp fuse would make 1380 watts. If the amp in question has two fuses for example would you just add the values of the fuses and then plug into the equation?/

What about what Terry said:

its more a good indication of an approximation of what kind of power might be possible in a perfect world..but given that formula some amps make more power than they should.

Tim

[Fishy]

Don't forget that no amp is 100% efficient.

But then again fuses don't blow right away. Its quite possible for current draw to momentarily exceed a fuse's rating. Music is very dyanamic. If you ain't playing test tones or seriously clipping things its awfully hard to get your "1000 watt" amp to produce that much power continuously.

Still when I see a "500 watt" amp with a 15 amp fuse I have to laugh.

All things considered I think adding a zero is a good guesstimate of an amplifier's potential. Just keep in mind a Class D is a helluva lot more efficient than a Class A, and that amps with non-regulated power supplies do produce more power at higher supply voltages.

[smoker]

So you use 13.8 as a happy medium?? I can understand that. It actually makes more sense. Given that formula a 1500 watt amp with a 100 amp fuse would make 1380 watts. If the amp in question has two fuses for example would you just add the values of the fuses and then plug into the equation?/

What about what Terry said:

its more a good indication of an approximation of what kind of power might be possible in a perfect world..but given that formula some amps make more power than they should.

for example a dx1500.1 has 120 amps worth of fusing but is rated at 1500 watts but has been tested at closer to 1900 watts or so.....