Power Amplifiers - Meaning, Types & Best Tips to Buy Power Amplifiers

The world of audio gear can seem like alphabet soup at first—amplifiers, preamps, integrated amps, receivers—it’s a lot. But once you understand what each component does, it starts to make sense.

Let’s start with the basics. An amplifier, or more specifically a power amplifier, is the muscle of your audio system. It takes a weak audio signal and boosts it enough to drive your speakers. That’s all it does—it doesn’t switch between sources or control volume—it simply amplifies the signal. But before the signal gets to the power amp, it usually passes through a pre-amplifier. The preamp is more of the control center—it takes the very quiet signal from your source (like a turntable, CD player, or streamer), gives it a little boost and allows you to control things like volume, input selection and sometimes tone. In more advanced systems, the preamp and power amp are two separate boxes, which can offer better performance but also cost more and take up more space.

Now, an integrated amplifier is a combination of those two things—the preamp and power amp—in one box. It’s a really popular choice, especially for people building a stereo system for music listening. It gives you the essential functions (source switching, volume control, power for speakers) in a single, streamlined package. Many integrated amps today also include digital-to-analog converters (DACs), Bluetooth, or phono stages for turntables, making them even more versatile.

Receivers are a bit different. Technically, a receiver is just an integrated amp with a built-in radio tuner, but in modern usage, “receiver” often refers to an AV receiver—something designed for home theatre use. These have multiple channels for surround sound, video switching, room correction software and support for formats like Dolby Atmos. They’re great for movies and TV, but they can be overkill for someone who’s just into stereo music listening.

If you’re just starting out with a stereo system, I’d strongly recommend going with a good integrated amplifier. It keeps things simple without sacrificing quality and it gives you room to grow without overwhelming you. Separates are great if you’re chasing ultra high-end performance and AV receivers make sense for home theater, but for pure music enjoyment, integrated amps strike the perfect balance.

Power amplifiers are rated in watts. 

For home use, your amp should be approximately 20W. For a venue that holds around 100 people with a live performance or gig (small-scale live event), a 20W tube amp, or a 40W solid-state amp would be appropriate.

The higher the power (watts), the louder and cleaner the speakers will play. Ultimately, it all depends on your listening habits and your speaker's efficiency.

Power amplifiers are widely used in audio applications, radio communication, car audio, live venues, and medical equipment (MRI) among several others. 

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, in common parlance, the receiver and amplifier might as well mean the same thing. However, they are not. There are subtle differences between the two. This guide by Ooberpad helps you understand the main differences between the two.

Benchmark power amplifiers are ultra-low-distortion, high-fidelity amplifiers designed for audiophile, studio and professional applications. They prioritise clean, uncoloured sound reproduction with minimal noise and maximum dynamic range. A prime example is the Benchmark AHB2, known for its THX-AAA (Achromatic Audio Amplifier) Class H topology, which significantly reduces distortion and improves efficiency. It boasts a THD+N as low as 0.00013% and a 132 dB dynamic range, making it one of the cleanest amplifiers available.

Key Advantages of Benchmark Power Amplifiers

✔ Ultra-Low Distortion & Noise – Provides near-perfect signal accuracy, making them ideal for critical listening and mastering studios.
✔ High Dynamic Range – Capable of reproducing the most delicate details in high-resolution audio.
✔ Class H Efficiency – Unlike Class AB or Class D amps, Class H dynamically adjusts power rails, minimising heat and improving efficiency.
✔ Balanced & Differential Design – Reduces interference and enhances signal purity.
✔ Flexible Power Output – Supports 100W per channel at 8Ω, 190W at 4Ω and 380W in bridged mode, making it compatible with a wide range of speakers.

Use Cases

• Audiophile Listening – Ensures transparent sound reproduction.
• Studio Mastering – Ideal for critical monitoring applications.
• High-Res Audio Systems – Pairs well with low-noise DACs for a pure signal chain.

Benchmark power amplifiers, particularly the AHB2, set a high standard for low-noise, high-accuracy amplification. Their THX-AAA Class H topology and balanced design make them superior to many traditional Class AB and Class D amps, making them a top choice for audiophiles and professionals seeking the purest sound reproduction.

Before we answer the question, let's breifly recap what we're dealing with. A power amplifier is a type of audio amplifier that supplies power to one or more speakers. Unlike home theater receivers, which come with extra features like radio, input source switching and AV processing, power amplifiers focus solely on amplifying audio signals. They lack built-in controls beyond a primary gain adjustment, similar to volume control. So yes, they can most certainly be used for home entertainment.

They come in various channel configurations, from monoblocks (single-channel) to stereo (two channels) and even multi-channel setups for surround sound. For home theater applications, you might encounter five, seven, or more channels. When more channels are needed, combinations of two-channel and seven-channel amplifiers can be used.

To use a power amplifier, you’ll need a separate preamp or AV preamp/processor. The preamp decodes or processes audio signals from sources like Blu-ray players, media streamers and others. These signals are then sent to the power amplifier, which drives the speakers. Connection options include RCA-type or XLR connections.

While home theater receivers have built-in amplifiers, some provide preamp outputs. By connecting external power amplifiers to these preamp outputs, you can enhance power output beyond what the built-in amps offer. Essentially, this turns the receiver into an AV preamp/processor.