Most audio systems require power amplifiers. Power amplifiers are widely used in audio applications, radio communication, car audio, live venues, and medical equipment (MRI) among several others.
It is one of the main components needed to connect music and the audience. It makes small signals bigger.
That said, any system that utilises speakers to produce sound will need a power amplifier. While most speakers have built-in amplifiers (known as active or powered speakers), in this article we will discuss external power amplifiers.
In this guide, we'll go through everything worth considering before you make any decisions about a power amp. But before diving into a comprehensive list of factors to consider while buying a power amplifier, let’s quickly understand what a power amplifier is, its intended applications and why you need one.
What Is A Power Amplifier, How Do They Function And Why Do You Need One?
A power amplifier is a device that sits between a sound source and a passive loudspeaker. It takes a line-level signal and makes it loud enough to fill a room or a venue with sound. It provides a constant high-voltage output minus any fluctuations in impedance or frequency response.
Whether it is a power amplifier for speakers or a professional power amplifier, the power amplifier is a device that amplifies the sound of the instrument and it boosts the performance of sound systems, including a home audio system in all kinds of situations.
Power amplifiers have one, two, or more channels. A mono power amp would have one channel, and a stereo power amp would have two channels.
Most power amplifiers have a power switch, which engages the device, and volume control that determines the device’s output level.
Power amplifiers are rated in watts, which is a unit of power. You should know how much power your speaker(s) can handle in order to determine how many watts you’ll need for your set-up.
Audio amplifiers are designed to work with 4-, 8-, or 16-ohm speaker loads, if the total ohm load of the loudspeakers is accurate for the amplifier, you can achieve optimal system performance.
For most people, it amplifies the sound of the instrument and boosts the overall performance of all kinds of sound systems, including a home audio system in many situations. Plenty of audio systems require power amplifiers and if chosen well, they will serve you for many years to come.
Also Read: Understanding the difference between AV Receivers and Amplifiers
Factors While Choosing A Power Amplifier For Your Speaker System/Home Theatre
Power amplifiers are essential to any speaker system or home theatre. They provide the necessary power to drive the speakers and ensure that they produce clear, distortion-free sound at high volumes.
There are several types of power amplifiers available in the market with several features and specifications.
- Power Output: The power output of an amplifier is measured in watts, and it determines how loud your speakers can get. You should choose an amplifier with an output that is appropriate for the size of your room and the type of speakers you have.
- Impedance: Impedance is the resistance of the speakers to the flow of electrical current, and it is measured in ohms. Select an amplifier that matches the impedance of your speakers, or one that comes within the acceptable range.
- Channels: The number of channels on an amplifier determines how many speakers it can drive. A 2-channel amplifier can drive two speakers, while a 5-channel amplifier can drive five speakers.
- Frequency Response: The frequency response of an amplifier determines the range of frequencies it can reproduce. Select an amplifier with a frequency response that matches the range of your speakers.
- Additional Features: Some amplifiers come with built-in equalisers, bass/treble controls, and digital inputs. These features help you gain more control over the sound of your system.
Ultimately, the best power amplifier for your speaker system or home theatre will depend on your needs and preferences. If required, consult AV professionals before making a purchase.
How To Choose A Power Amplifier
A power amplifier is critical to the quality of the sound system. Here’s a quick amplifier specs sheet for you to consider before making the power amplifier purchase.
- The Distortion Dilemma Amplifiers come in four classes A, B, AB and D. These classes are closely interrelated with Total Harmonic Distortion(THD). The lower this distortion, the more accurately the sound will reciprocate the original. Class A amplifiers are perfect for this, but their power efficiency is just 20%and they generate a lot of heat. Class B pulls and pushes, which leads to about 75% percent efficiency but the THD levels are much higher. AB strikes the perfect balance. Class D 90% efficient but the sound quality is poor as compared to others. For this reason, they are more suitable for low-end HTiBs.
- The power output (Watts) is related to how loud your amplifier can pump out music. A bigger room needs a higher wattage. That said, if you’re listening to music at home anything between 20W and 50W will be more than enough.
- Pay close attention to speaker sensitivity. If the speaker sensitivity is rated low, you will need more amplification to reach higher listening levels. Bear in mind the impedance rating of the speakers. If your speakers have an impedance lower than four ohms, you need to look for a high current amp.
- Consider specs like signal to noise ratio (S/N), crosstalk and dynamic headroom
- Signal-to-Noise Ratio: An amplifier always has a slight buzzing noise inside of it. A good amplifier cuts down this whizz. The bigger the numerical value of the S/N ratio, the more superior sound you’ll get.
- Crosstalk: A measure of how much undesirable left signal is mixing with the one on the right and vice versa. The more the crosstalk, the worse the stereo sound impacted. In the measure of crosstalk, 100dB means a better stereo separation than 60dB.
- Dynamic Headroom: A measure of the amplifier’s ability to output power at a much higher level for a short time.
- Ensure you have a sufficient number of inputs. Options available include stereo audio (RCA), HDMI Optical or a digital coax. If you're using stereo audio, it consists of two channels of audio 5.1 surround or digital audio is not supported. Digital coax uses an RCA cable to pass a 5.1 surround signal. Optical cables use light to pass a 5.1 signal. RCA cables are an “unbalanced” connector as compared to the TRS and XLR, which are fairly balanced. A balanced cable is less prone to interference and can carry low signals over longer cable lengths. If your cable length is between two and five metres, you can use the RCA cable. If the cable length spans over that range, you need to use the TRS or XLR.
Also Read: Power Amplifiers - Meaning, Types & Best Tips to Buy Power Amplifiers
When you’re looking at speaker wire connectors, you can choose the pin connector, the spade lug and the banana plug. The pin connector comes in less expensive receivers and speakers. It looks like a straight or angled pin at the end of the wire. The spade plug is the most reliable but can be a tedious connection choice. The banana plug is user-friendly and comes close to the quality which the spade plug provides.
When buying amplifiers, the focus should be on finding the harmony between sonic integrity and power. You need to consider all these specifications. Extreme power will be of no use if distortion is high and excessive background noise can ruin even the nicest sound quality.
There is a lot to keep in mind when buying power amplifiers and if It’s not a task you want to take up single-handedly, we are here to help! Head on over to check out our best power amplifier brands and reach out to our experts so they can help you determine which power amplifier will best suit your needs