power effieceny of amplifiers

[Dragonknell 10+ year member]

I did'nt even think about this before, what exactly is the power efficeny of an amplifier? if its rated at 800 watts rms, its that output or how much it uses? if it has specs posted at 800, and pulls 800, and has 90% efficieny wouldnt it be closer to high 600s rms? or does it drawl 1000 and output 800?

Of course it could have 100% effieceny, but seeing as amps get pretty hot it isnt likely.

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[ANeonRider 10+ year member]

depends on its design.

Class A is quite inefficent(like around 30-40% I believe)

Class AB is a little better (around 50-65%)

Class D is great (75-85% maybe higher)

and in your example, the amplifier pulls 1000(they don't pull power, they draw current btw), and output (source current) 800.

 

[jleecong 10+ year member]

Very simular topic I started.

http://www.caraudio.com/vb/showthread.php?t=62547

 

[Dragonknell 10+ year member]

sorry for the errors (current), so im going to be very pressed on power/current; having a 90amp alternator, and a stock batter; with a 800 watt rms class d amp (either a8000t or Hifonics Brutus, depending on ampere drawl or efficeny) and a 150 dc to dc 90% effieceny power supply.

That means that with both of those running, not including my normal car stuff... that my battery will be constantly draining ?

So should i be watching power ouput as in watts

or

overall ampere drawl?

watching amps with everything on in my car including ac full blast im guessin at 35 amps, the hifonics brutus is like 40 amps? and the power supply unit is 150 watts so nominal

But 800 watts rms and 150 watts rms not including car standards

could somoene explain this

 

[ANeonRider 10+ year member]

Not likely, you will not be pulling the full amount of current all the time, heck prolly won't ever pull the max.

BTW, when the manufacturer rates their output, it is output, not what the amp pulls.

 

[Dragonknell 10+ year member]

i figured that lol //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif it'd sell better

So should i be watching power ouput as in watts

or

overall ampere drawl?

watching amps with everything on in my car including ac full blast im guessin at 35 amps, the hifonics brutus is like 40 amps? and the power supply unit is 150 watts so nominal

But 800 watts rms and 150 watts rms not including car standards

could somoene explain this

 

[jleecong 10+ year member]

Output and Current Draw are directly related.

The more you draw the more you output the more you output the more you draw.

 

[Dragonknell 10+ year member]

then the 40 amps on the brutus is underrated?

 

[jujumantb 10+ year member]

depends on its design.
Class A is quite inefficent(like around 30-40% I believe)

Class AB is a little better (around 50-65%)

Class D is great (75-85% maybe higher)

and in your example, the amplifier pulls 1000(they don't pull power, they draw current btw), and output (source current) 800.

Take about 15% off all those efficiencies and you are more in the ballpark.

 

[ANeonRider 10+ year member]

Take about 15% off all those efficiencies and you are more in the ballpark.

Figured I was off a bit, in theory that is the effiecencies of the designs, but you know how far theory gets us sometimes //content.invisioncic.com/y282845/emoticons/spank.gif.0d78e34d42ea8780359e903aeb6697d6.gif

 

[jleecong 10+ year member]

then the 40 amps on the brutus is underrated?

Read my thread.
"Using the formulas above even at 100% efficiency I don’t see how the Hifonics can output 1000W RMS if can’t draw more than 60amps."

Answer

"That amp use slow blow fuses. The fuses can take twice their rated current draw for a few minutes of constant power draw."

 

[Dragonknell 10+ year member]

so then this hifonics brutus will be pulling over 1200 watts. and outputing 800 watts rms. Basicly im going to need a new alternator... ghay.

Even with a farad cap... and a new batt...

 

[jleecong 10+ year member]

so then this hifonics brutus will be pulling over 1200 watts. and outputing 800 watts rms. Basicly im going to need a new alternator... ghay. Even with a farad cap... and a new batt...

It will pull current (amps) and output watts.
With one 1000W amp and a 90A alt you should be OK as long as you don't sit at stop lights with it on full blast. May want to upgrade/replace you battery if it has some age as a good battery can help prevent a lot of problems.

I myself purchased a yellow top and will be using my factory (original) 90A alt to power a 1000W Sub amp and 150W highs amp.

 

[94gmsierra 10+ year member]

what about a class T amp?? where do these fall in range of effieciency, and exactly how are these amps digital???

 

[jujumantb 10+ year member]

what about a class T amp?? where do these fall in range of effieciency, and exactly how are these amps digital???

They arent. Those are basically full range class D amps IIRC. So I'd guess they have about the same efficiency of class D (~65-70%)