How a Motorcycle Stereo Amplifier Works

So you're thinking about investing in a stereo system for your motorcycle? Doing so is a great way to enhance your riding experience by adding the joy of music. Rather than riding in silence, you can listen to all of your favorite tunes. A stereo system may also increase the value of your motorcycle, allowing you to sell it for a higher price when, or if, you decide to sell.

Most people are familiar with the basic components of a motorcycle stereo, including the source/deck and speakers. However, a component that often goes unnoticed is the amplifier. But don't let that fool you into thinking the amplifier is some trivial piece of equipment with no real purpose. On the contrary, it plays an important role in both the quality and volume of a stereo system.

A stereo amplifier is essentially an electronic device that amplifies low-power sound waves so they are more suitable for loudspeakers. Amplifiers have actually been around for over a century, with Lee De Forest inventing the world's first functional amplifier back in 1909. This crude amplifier consisted of a three terminal triode with a control grid that managed the flow of electrons. Early model stereo amplifiers such as this used vacuum tubes (valves) to propagate the sound. Today, though, they've been replaced by amplifiers using solid-state devices like BJTs, FETs and MOSFETs.

Without getting too deep into the technical side of things, the purpose of a stereo amplifier is to magnify the electrical currents that make up the sound. Most decks and motorcycle speaker systems have amplifiers built into them, enhancing the sound even further from its original state. These default amplifiers generally lack the power to deliver high-quality sound signals to premium speakers; thus, you need a dedicated amplifier for the job.

It's important to note that you'll typically want one channel for each speaker on your motorcycle. Let's say you have a total of four speakers installed on your motorcycle. In this scenario, you would need an amplifier with at least four channels.

When choosing a motorcycle amplifier, you may come across terms like “RMS” and “Peak Power.” The RMS (or continuous power) is defined as the amount of power (measured in watts) that an amplifier is able to produce. The RMS rating on an amplifier should match the rating of your speakers and is the most important rating as it directly relates to the quality and volume output. Peak Power, on the other hand, is the wattage amount that an amplifier can only generate for brief periods of time. Peak Power is always higher than the RMS.