Everyone knows you need an amplifier in your car’s audio system if you want thumping, window rattling, trunk vibrating bass, but adding an amplifier will provide so much more than you expect. With a high quality amplifier you’ll get much better overall sound quality. And if you’ve upgraded your speakers or added a new subwoofer, a separate amplifier will provide the power needed to get the most out of them. It will provide the power that the amplifier inside a dash mounted receiver just can’t deliver.


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Amplifiers are categorized according to classification, number of channels, and power rating in watts. The class of an amplifier refers to its circuit design. There are Class A, Class B, Class A/B and Class D amplifiers, with the latter two being the ones most commonly used in car stereo applications. Class A amplifiers feature simple design, the highest linearity over other amplifier classes, and produce the best sound quality. However, they are inefficient because current flows through their output transistors all the time.

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Class B amplifiers are the most efficient because the output transistors pass current only when there is an audio signal, but they produce a lot of distortion. Class A/B amplifiers are a combination of the Class A and the Class B amplifiers, with a small amount of current flowing all the time, even when there is no audio signal, which results in greater efficiency with almost no distortion. Class A/B amplifiers are one of the most common used types of audio power amplifier design. In a Class D amplifier the transistors are switched on and off. Class D amplifiers are more efficient than Class A/B but produce more distortion. However, this distortion can be removed with a filter.

Before choosing an amplifier for your audio system, you need to decide how you intend to use it and how many channels it should have. Usually, the number of channels should match the number of speakers in your system. As the name suggests, a mono amplifier is designed for one speaker, usually a subwoofer, however two subwoofers can be connected to a mono amplifier. 2-channel amplifiers are for two speaker systems, 4-channel for 4 speaker systems, and 5-channel amplifiers are for 4 speakers and a subwoofer. Some amplifiers can be “bridged”, meaning 2 channels can be combined into one for more power. A 4-channel amp could power two speakers and then have the remaining channels bridged to power a subwoofer.

The amplifier’s power rating should coincide with your speakers’ RMS, or continuous power rating. If this rating is given in a range, go with the higher number. This is especially important to get maximum performance from aftermarket speakers. For best sound quality the amplifier should deliver at least 75% of the speaker’s RMS rating, and the average speaker can handle up to 150% of this rating without any problems. It’s always better to overpower speakers rather than under power them. The distortion caused when you make the most of a low-powered amp is more likely to harm a speaker than too much power. If you’re building a system from scratch, a small car won’t need as much power as a larger vehicle.

In addition to the mentioned above, there are other features that you’ll commonly see in amplifier listings, like filters and bass boost. There are high pass and low pass filters. A high pass filter removes low frequencies so the amplifier is only boosting the high frequencies sent to small speakers for high notes, while the low pass filter takes out the high frequencies, such as would be common when powering a subwoofer. Variable filters allow you to select the frequency to be filtered. Variable bass boost control allows you to increase the bass level to tailor the sound quality. Whatever amplifier you need, on our website you'll surely find the right product for your audio system.

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Guides & Articles

  • Amplifiers
    Car Audio System Wiring Basics
    In this article, we'll discuss the basics of your vehicle's audio system wiring. Specifically, we'll look at the addition of one or two amplifiers to your system, and examine the steps involved for both the mechanical and electrical installation. Refer back to these two illustrations while reviewing the text.

Car Amplifiers Reviews

Average rating:  5  4.9 - 69 reviews
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5 of 5
A Bang For Your Buck
Really impressed with the price you get a really good, only one small problem the amp stays hot, so you need a good fan to keep cool, but keeping it cool this has no problems pushing what you got for the price well well worth it just remember keep it cool.
SPosted by Shawn T (Thomasville, NC) /
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