Stereo Amplifiers Explained in a Nutshell GA S REGULAR Menu Lifewire Tech for Humans Newsletter! Search Close GO Home Theater & Entertainment > Audio 198 198 people found this article helpful
What Are Stereo Amplifiers and How Do They Work?
What does your amp do for your sound system?
By Gary Altunian Gary Altunian Writer Gary Altunian was a freelance contributor to Lifewire and industry veteran in consumer electronics. He passion was home audio and theater systems. lifewire's editorial guidelines Updated on December 28, 2020 Tweet Share Email Kirby Hamilton/Getty Images Tweet Share Email Audio Speakers Soundbars Stereos & Receivers It's easy enough to purchase new/replacement stereo components and hook it all up for fantastic results. But, have you thought about what makes all of it tick? Stereo amplifiers can be a critical element for best audio performance. What Is an Amplifier
The purpose of an amplifier is to receive a small electrical signal and enlarge or amplify it. In the case of a pre-amplifier, the signal must be amplified enough to be accepted by a power amplifier. In the case of a power amplifier, the signal must be enlarged much more, enough to power a loudspeaker. Although amplifiers appear to be big, mysterious boxes, the basic operating principles are relatively simple. An amplifier receives an input signal from a source (mobile device, turntable, CD/DVD/media player, etc.) and creates an enlarged replica of the original smaller signal. The power required to do this comes from the 110-volt wall receptacle. Amplifiers have three basic connections: an input from the source, an output to the speakers, and a source of power from the 110-volt wall socket. Amplifier. Daniel Limpi / EyeEm How Does an Amplifier Work
The power from the 110-volts is sent to the section of the amplifier – known as the power supply – where it is converted from an alternating current to a direct current. Direct current is like the power found in batteries; electrons (or electricity) flow only in one direction. Alternating current flows in both directions. From the battery or power supply, the electrical current is sent to a variable resistor – also known as a transistor. The transistor is essentially a valve (think water valve) that varies the amount of current flowing through the circuit based on the input signal from the source. A signal from the input source causes the transistor to reduce or lower its resistance, thereby allowing current to flow. The amount of current allowed to flow is based on the size of the signal from the input source. A large signal causes more current to flow, resulting in greater amplification of the smaller signal. The frequency of the input signal also determines how quickly the transistor operates. For example, a 100 Hz tone from the input source causes the transistor to open and close 100 times per second. A 1,000 Hz tone from the input source causes the transistor to open and close 1,000 times per second. So, the transistor controls level (or amplitude) and frequency of the electrical current sent to the speaker, just like a valve. This is how it achieves the amplifying action. Image provided by D&M Holdings Getting Sound
Add a potentiometer – also known as a volume control – to the system and you have an amplifier. The potentiometer allows the user to control the amount of current that goes to the speakers, which directly affects the overall volume level. Although there are different types and designs of amplifiers, they all operate in this similar manner. Was this page helpful? Thanks for letting us know! Get the Latest Tech News Delivered Every Day Subscribe Tell us why! Other Not enough details Hard to understand Submit More from Lifewire How to Use a Speaker Switch for Easy Multi-Room Audio What is a PSU? What is an ATX Power Supply? The Complete Guide to Home Audio Systems for Beginners How to Fix Common Car Amp Problems What Are Diodes and What Are They Used For? What to Do When the Subwoofer Isn't Working Properly How to Make Wired Speakers Wireless How to Improve FM Antenna Reception The Truth About Wireless Speakers for Home Theaters How to Connect a Subwoofer to a Receiver or Amplifier The Difference Between Home Theater and Stereo Receivers Passive vs. Active GPS Antennas What Is Wireless Home Theater? Coaxial vs. Optical Digital Audio Cables 5 Applications of Inductors You Should Know The 3 Best Car Stereo Systems of 2022 Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies