Amp current draw question

[hatedonmostly 5,000+ posts]

On average, how much current does, let's say, a 1200W amp draw that is fused at 120A? With gain set appropriately to 1200W, at full tilt, perfect voltage, etc.

I know fuses can take more current than they are rated for for short bursts, but I was also told that amps don't constantly pull their max fused rating unless there is some sort of issue with the install; such as poor ground, etc. Would just like to be enlightened on the subject.

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[Ge_off_me 5,000+ posts]

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[SicAudio 5,000+ posts]

hard to say

lots of variables come into play

box rise has a huge effect on current draw...

need a ton more info to answer it...even to get anywhere close...

 

[Ge_off_me 5,000+ posts]

How about we say DSC1500

 

[hatedonmostly 5,000+ posts]

hard to say
lots of variables come into play

box rise has a huge effect on current draw...

need a ton more info to answer it...even to get anywhere close...

I'm not trying to be 100% specific, just want a rough idea...I know that we'll never know the entirety of it, since music is too dynamic.

I just want a rough idea. Let's say a AQ1200D. It's fused at 120A. Consistently, under perfect conditions, will it pull ~60A? 80A? 100A? I doubt it will pull the full 120A it is fused at consistently...

 

[CHEMMINS 10+ year member]

On average, how much current does, let's say, a 1200W amp draw that is fused at 120A? With gain set appropriately to 1200W, at full tilt, perfect voltage, etc.
I know fuses can take more current than they are rated for for short bursts, but I was also told that amps don't constantly pull their max fused rating unless there is some sort of issue with the install; such as poor ground, etc. Would just like to be enlightened on the subject.

Current = Amps.

So therefore....in a perfect world, an amp that is 100% efficient, a 120a fused amp with a alternator voltage of 14.4 would yield 1728 watts at full tilt.

In reality.....

Amps are 75% efficient. So at that rate.....even if the full 120 amps is being sent through the fuse (which it isn't) you get 1296 watts.

Give or take voltage floating.....say a sustainable 13.8 volts. You would get 1242 watts full tilt.

You are gonna play your amps at most 3/4 volume to avoid clipping. So that would be - 931.5 watts

Average listening volume on your deck will be 50% so in reality you will actually hear 465.75 watts.

 

[hatedonmostly 5,000+ posts]

Current = Amps.
So therefore....in a perfect world, an amp that is 100% efficient, a 120a fused amp with a alternator voltage of 14.4 would yield 1728 watts at full tilt.

In reality.....

Amps are 75% efficient. So at that rate.....even if the full 120 amps is being sent through the fuse (which it isn't) you get 1296 watts.

Give or take voltage floating.....say a sustainable 13.8 volts. You would get 1242 watts full tilt.

You are gonna play your amps at most 3/4 volume to avoid clipping. So that would be - 931.5 watts

Average listening volume on your deck will be 50% so in reality you will actually hear 465.75 watts.

I was following you until I reached this point; I disagree with this here, if the gain is set to match the preout voltage, the amp will produce 100% of it's output without overdriving itself (under perfect conditions of course). Example, if you have a deck with 8v preouts, you don't have to turn the gain up all of the way to get the output from the amp, any further than matching the voltage of the HU will just overdrive the amp.

But I have an thought. The amp is rated to put out 1200W, so if we take the equation V*C=P,

14.4v * 120A = 1728W

80% efficiency, so:

1728W * 0.80 = 1382.4W

That's over what the amp's power rating is, so if we divide by 14.4 to get the actual amperage it pulls...

1382.4W / 14.4v = 96A

So in theory, this theoretical amp should draw 96A of current at the very most under perfect conditions? This, of course, would be on be on a tone and actual musical current draw would be much less

 

[SicAudio 5,000+ posts]

Current = Amps.
So therefore....in a perfect world, an amp that is 100% efficient, a 120a fused amp with a alternator voltage of 14.4 would yield 1728 watts at full tilt.

In reality.....

Amps are 75% efficient. So at that rate.....even if the full 120 amps is being sent through the fuse (which it isn't) you get 1296 watts.

Give or take voltage floating.....say a sustainable 13.8 volts. You would get 1242 watts full tilt.

You are gonna play your amps at most 3/4 volume to avoid clipping. So that would be - 931.5 watts

Average listening volume on your deck will be 50% so in reality you will actually hear 465.75 watts.

to the rescue!! lol ty Chem //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I am too tired to think 1/2 straight lol

in reality/ general... maybe 60-70 amps at a normal volume...90-100 when ur thumping it hard for a certain song..

 

[hatedonmostly 5,000+ posts]

to the rescue!! lol ty Chem //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
I am too tired to think 1/2 straight lol

in reality/ general... maybe 60-70 amps at a normal volume...90-100 when ur thumping it hard for a certain song..

Well I'm talking full tilt...I'm not concerned with what "normal volume" current draw would be, since "normal volume" is relative //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

But I just did the math above and that seems correct, in theory, 90-100 should be the max draw at full tilt.

 

[SicAudio 5,000+ posts]

yes ( i said 90-100 ) //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[hatedonmostly 5,000+ posts]

Good stuff. Thanks for your help guys...

 

[CHEMMINS 10+ year member]

Hehe....no worries. And remember....no one is setting their gains properly unless they are doing it with an O-scope.

 

[hatedonmostly 5,000+ posts]

Hehe....no worries. And remember....no one is setting their gains properly unless they are doing it with an O-scope.

Ha, I barely ever use my multimeter to set gains...besides, everyone clips in car audio, it's inevitable.

 

[SicAudio 5,000+ posts]

very true //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I use my ear... fast and accurate for me. but I have setup 10000's of amps in 25 years as a profession... learned the hard way how to do it right when I was young lolz

paying to replace new stuff in the late 80's when it was horribly expensive teaches you very fast lol

 

[CHEMMINS 10+ year member]

For the price of a scope now though, you can get the most out of your system using it.