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Amplifier Installation

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     Here's a little information about Amplifier Power Ratings. Amplifier Power Ratings is a matter of doing the math. Volts x Amperes = watts. There is RMS (continuous) and Max/Peak (for brief musical peak) power ratings. Most Amplifiers advertise their "Max/Peak" power, Even include those ratings as printed numbers on the outside casing and even in the model number.  Most Amplifiers also include their RMS (continuous) power output. Which is usually about 50% of the their peak power. RMS power is the most significant rating. And is also the power rating for which the volts x amperes = watts are based. Also, what voltage input is also significant. Most Amplifiers power ratings are rated with a 14.4v input, Some with a 13.8v input and even some with a 12.5v input. Keep in mind that a cars electrical system also has to supply and keep up this amp input voltage. Most cars' electrical systems cannot supply the 14.4 100% of the time. As a matter of fact, most Factory systems supply about 13.8v on average. The more the cars elecrical system is demanded, the more it has to supply. If an amp requires more amperes (current), then the cars elecrical system has to be able to supply these amperes, this is where the alternator is more significant. And will need to be upgraded.  


     If an Amplifier does not include the input voltage at which is was tested, then it's power rating is pretty much meaningless. If you see an Amplifier with a power rating of say, 2000 watts and only has a, lets say, a 40 amp fuse, You can rest assured, it really doesn't push 2000 watts, if you "do the math"...... a 40 amp fuse x 14.4v = 576 watts. So, there is no way that amp can push 2000 watts. You can do the math in reverse, 2000 watts divided by 14.4v input voltage =  138 amperes. So, as you can see, there is no way that 40 amp fuse is going to allow the amp to push 2000 watts. That fuse would pop way before 2000 watts.

     Given the same output power, if you have the input voltage, you will need less amperes (current) to make that power. If you have less input voltage, the amp will need to be able to draw more amperes (current) to push the 2000 watts.

     If an amp has a 14.4v input rating, and your cars elecrical system can only supply 13.8v, that amp will never push/get to it's rated power. Again It's simple math. Also, all of this is assuming an amp can operate at 100% efficiency, for they do not. Most Class A/B Amp's operate at about 75% efficiency. Class D Amp's are a little more efficient and operate at about 90%. And in turn, produce less heat. But these are only good for bass frequenies. Class D Amp's were designed just for this task. Class D Amp's have a limited frequency response, which is around 20hz-200/250hz. Their high efficiency is pefect for driving subwoofers, especially considering subwoofers need a lot of power. This is because, bass frequecies require a lot of power.  


     For an Amplifier to supply the amperes (current) to push BIG power, they also need to be Built that way. And this, is NOT cheap!


     Understanding a Cars charging system:

     The charging system consists of the battery, the alternator and starter. Basically all the battery does is start the vehicle and supply power when the engine is not running. This is the reason you only see a 12.5v (or so) reading on the voltage gauge when the engine is not running. When the engine is running, that 12.5v increases to as much as 14.4v. This depends on how good the electrical/charging system is, which includes the alternator, the alternator operating is what increases the voltage from 12.5 to 14.4. Modern vehicles, with their power everything and big displays require a big alternator and usualy comes with one from the factory. But only big enough to handle whatever the vehicle came with. Anything that "tasks" the electrical system, puts a strain on the electrical system and will require more amperes (current). This is the alternators job. If the current draw is more than the alternator can handle, then that "draw" will tap into the battery, this is where you see "dimming lights" and with that a significant voltage drop. if this ever happens, a higher ampere output alternator is required.  

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