Whether you’re enjoying a film on your home cinema or listening to your favorite music in the car, good sound quality is vital.

Even if your TV has amazing picture quality you won’t be able to enjoy it as much if the sound is incomplete or distorted. Many people think good audio is all about speakers but they can only do so much by themselves.

Often if you have passive speakers without an inbuilt amplifier, your laptop, car radio, or TV box won’t be able to produce a signal that is strong enough to power them.

This can lead to all sorts of problems such as a lack of bass or high frequencies, fuzzy incomplete sound, and even distortion.

The problem here isn’t your speakers, it’s that the device you are using to power them can’t make use of their full potential. For solving this problem the only answer is a good amplifier.

Class D amps are compact, energy-efficient amplifiers that have become the go-to choice for many people looking to improve the sound quality of their speakers.

While they may not output the highest-fidelity sound they will still make a massive difference to the audio from your passive speakers.

To help you pick the right amplifier for your needs, we’ve composed the list showcasing some of the best class D amplifiers available to buy online.

Fosi Audio BT20A Bluetooth 5.0 Stereo Audio 2 Channel Amplifier

Many amplifiers are connected to a pair of speakers via RCA cables, but some of them can pair with devices via Bluetooth.

This is the case with Fosi Audo’s class D amplifier which can connect to any compatible device using Bluetooth 5.0.

Don’t worry if your speakers can’t connect in this manner, as this model can also be hooked up using a regular RCA cable.

With a very low THD, this amp produces hardly any distortion and has a maximum output of 2x 100w. This means despite its incredibly compact design this amp is capable of driving the small to medium-sized speakers often used in home cinemas.

There are inbuilt bass and treble knobs so you can easily alter your sound output however you prefer and the high-performance chips in this amp provide crisp highs and lows for a fuller sound.

The Bluetooth has a range of up to 50ft, but you shouldn’t have the amp too far away from your speakers or you may encounter glitches and skips in your audio.

Pros:

• Bluetooth 5.0 and RCA inputs – Connect your amp to your speakers, phone, or laptop via Bluetooth from up to 50ft away or plug it in with a standard RCA cable. 
• THD <0.04% – You won’t experience much distortion with this amp even at high volumes. 
• Bass and treble knobs – Makes it easy to control the output of your amp. 
• High Power output – This compact class D amplifier can drive some surprisingly large speakers.

Cons:

• Bluetooth can glitch – The Bluetooth says it has a range of 50ft, but moving the amp too far away from a paired device may cause glitches and skips in the audio.

Rockford Fosgate R500X1D Prime 1-Channel Class D Amplifier

If you are looking for an amplifier to improve your car’s speakers then look no further.

The Rockford Fosgate is designed to be hooked up to your vehicle’s sound system so you can listen to all your favorite songs the way they were meant to be enjoyed.

This model has a maximum power output of 500w x 1 making it suitable for most speakers and small subwoofers. 

Connecting this amp to your car’s speaker may require a bit of DIY as well as AWG cable, but once you do, your music will sound much better.

There are two sets of EQ controls and a phase wheel for adjusting the amp’s output to your preferences. 

Since it is designed for a car, you shouldn’t use this amp for home speakers, as it will likely overpower them and cause irreparable damage.

The aluminum heatsink is there to ensure the amp doesn’t overheat, and other safety features have been included to protect against voltage spikes and short circuits.

Pros:

• EQ controls – Allow you to adjust the amp’s output.
• MOSFET power supply – Offers high efficiency at low voltage so this amp can function off your car battery.
• Aluminum heatsink – Prevents overheating 
• 500w x 1 – This amp is easily powerful enough to drive small subwoofers for extra bass while listening to music in your car.

Cons:

• Too powerful for regular speakers – this amp is designed for car stereos and may overpower regular low-watt speakers.

S.M.S.L AD18 HiFi Audio Stereo Amplifier

Subwoofers are larger speakers that specialize in producing low bass frequencies. If you are a fan of deep, rumbling bass, then a good set of subs is essential.

The problem is that since many of these speakers are so large, most amps don’t have sufficient wattage to power them but this 2 x 80w amp from S.M.S.L does.

This amp can be connected via Bluetooth 4.2, a standard RCA cable, or USB. The 1.44In color display makes it easy to switch between the amp’s different functions and monitor its output for the sound you want.

There is a handy 3.5mm headphone jack for plugging in your headset if you want to use this amp for listening to music or for music production.

The matt aluminum casing for this amp not only looks stylish but it also helps to cut down on interference.

This will prevent your speakers from feeding back as well as ensuring crystal clear sound quality.

Included in the box is a remote control so you can fiddle with the amp’s output from the comfort of your sofa.

Pros:

• 6 different inputs – Including RCA, USB, and Bluetooth 4.2. 
• Remote control included – The wired remote means you don’t have to get up every time you want to adjust the amp. 
• Aluminum casing – Reduces interference 
• 80W x 2 output and 0.04% THD – This amp can power small subwoofers and passive speakers without producing lots of distortion.

Cons:

• Small ports – Both the input and output ports on this amp may be too small for some RCA cables.

Pyle Bluetooth HiFi Mini Audio Amplifier

If you are looking for a high-quality amp that will power your speakers without breaking the bank, look no further than this model made by Pyle.

This 2x100w amplifier has everything you could possibly need for better sound quality in one compact device.

With a THD of less than 0.04%, you can expect clear audio with practically no distortion, even at higher volumes. 

The bass and treble controls make it easy to adjust your amp’s output as you need. With the output being as high as it is, you shouldn’t have any problem hooking the amp up to your speaker set, unless they are extremely large.

Furthermore, its incredibly compact size means that you won’t have trouble finding the necessary space for adding this device to your current setup. 

One of the best features of this amp is the versatility offered not just by its size but also by its inputs.

There is an antenna for connecting the Pyle to your phone, radio, or laptop via Bluetooth 5.0 from up to 30ft away, as well as ports for RCA cables.

Pros:

• Compact and portable – This device can fit anywhere near your speakers without taking up lots of space. 
• Bluetooth 5.0 – As well as RCA cables, you can connect devices to this amp from up to 30ft away with Bluetooth 5.0. 
• Bass and treble controls – Adjust the levels on your speaker’s output with ease.
• 2x 100W output- This amp won’t have any trouble powering most small to medium-sized speakers.

Cons:

• Both channels may not work with Bluetooth – Some users have reported that only one channel works when connecting devices to the amp via Bluetooth

Planet Audio TR3000.1D Class D Car Amplifier

This is another amplifier for your car but unlike the last one we looked at it is capable of generating up to 3000W. Using this amp for smaller speakers will quickly overpower them and probably cause irreparable damage.

However, if you enjoy loud bass and have a large subwoofer installed in your car, this is the perfect class D amplifier for driving it. 

The MOSFET power supply helps this amp to generate the power it needs, and you can pair this unit with a second amplifier if you need to power two sets of speakers.

There are plenty of controls for setting a low-pass and subsonic filter as well as a bass boost for when you really want to crank the volume. 

There are several safety measures in place to shut the device down if it overheats or encounters a voltage spike.

This amp will allow you to unlock your subwoofer’s true potential, which is exactly what you want if you enjoy listening to loud, bass-heavy music in your car.

Thanks to the remote, you can easily adjust the volume of your sound system without fiddling with the amp itself.

Pros:

• MOSFET power supply – Allows this amp to generate enough watts for driving large subwoofers. 
• Can be paired with another amp – Strap two of these amps together for 6000W of power at 2 Ohms of impedance. 
• Low-pass and subsonic filter- Adjust the frequencies being put through to your subwoofer for cleaner bass 
• Bass boost – For deep rumbling bass whenever you want it.

Cons:

• For vehicles only – Unless you have an enormous speaker stack at home, this amp should only be used in your car.

Buyer’s Guide

Shopping for a class-D amplifier can be tricky but if you get the right one it will make a massive difference to your home cinema or car’s sound system.

There is a lot to take in when shopping for any audio equipment, and it is important to buy an amp that is compatible with your current setup.

Choosing the wrong product could lead to unsatisfactory results at best or broken speakers at worst so here are a few things to consider when buying a new amp. 

Power Output

The first thing you should look at when searching for an amplifier is the speakers you are going to connect it to. The root mean square power (often shortened to RMS) is how much power an amp can generate measured in watts.

This number is often just how much continuous power the device has for driving your speaker, while the peak power denotes the maximum capacity during a surge, such as a loud section in a piece of music.

Ensure that the number of watts consumed by your speakers is equal to or greater than the amp’s output. A 100w amp will easily overpower 50w speakers and may cause permanent damage if it does. 

If an amp has multiple channels its power output might be labeled differently; for instance, a two-channel amp may have an output of 2 x 50w. What this means is that the amp can produce 50w per channel for a total of 100W across the pair of speakers.

Often the power output will be stated at a certain level of resistance, such as 1500W @ 4 Ohms. This is how well the amplifier works at varying levels of resistance.

If your sound system has greater resistance the amp will produce proportionally less power which is another reason to always double-check your speakers before buying an amp. 

THD

Another term you may come across is Total Harmonic Disorder or THD for short.

Simply put this is a measurement of how much distortion an amp produces and as such you want this number to be below 0.04% for crystal clear audio.

Most amplifiers will still produce some distortion at very high volumes but bigger amps will be able to handle louder outputs before the interference becomes noticeable. 

Bass and Treble Controls

Equalization is the process of altering the volume of specific frequencies to eliminate feedback and improve audio quality.

If you want more control over the sound from your amp, you’ll want to buy one that has bass and treble knobs so you can equalize the output. These controls will allow you to balance your sound for perfectly clear audio. 

Are you buying for a car or a home theatre? 

Different amps are best suited to different jobs. A small 50-100W amp will be enough for powering small to medium passive speakers.

If you want to drive large subwoofers for listening to bass-heavy music in your car then you will need something significantly more powerful. 

Bluetooth Input

Many amps have the option to connect via Bluetooth, which allows them to sync with your smartphone or laptop without a cable.

Bluetooth 4.2 and 5.0 are both good enough for listening to music with minimal disruption, however, if your device is too far away, the audio may start to cut in and out.

RCA is a much more stable means of connecting your amp to a set of speakers, and thankfully many models out there have the option to use both.

If you do want to try going wireless, make sure the device you want to pair has Bluetooth 4.2 or 5.0 to avoid any connection issues. 

Frequency Response 

This is the range of frequencies an amplifier will recognize and send through to the speaker. For most amps, this is between 20Hz to 20Khz but those designed to drive large subwoofers will have a slightly different range for producing extremely low bass frequencies. 

Safety Precautions 

As with buying any electronics, it is vital to pick products that have all the appropriate safety measures in place. Before you buy an amp you should check what kind of fuse it has to deal with voltage spikes and short circuits.

If you are looking for a more powerful amp for bigger speakers, you may need to also check that the MOSFET power supply has a decent heatsink to prevent any issues arising from overheating.

Frequently Asked Questions

What is a Class-D Amp?

An amplifier is any device that increases the strength of a signal. Class D amplifiers take audio inputs and boost them so that they can be output by your speakers at higher quality. 

There are five main classes of amp including A, B, A/B, C, and D? Of the five classes A produces the highest fidelity sound but is the least efficient at doing so.

In comparison class- D amps are slightly lower fidelity but can operate at roughly 90% efficiency making them a great choice for cars and home sound systems. 

How can I tell if an amp is powerful enough for my speakers?

Generally speaking, it is better for your amp to be underpowered than overpowered. A 50W amp will power 100w speakers, but a 100w amplifier would probably break 50w speakers.

If you want to drive large subwoofers, you will need to check that the amp you are looking at is capable of doing so before you buy. 

Last update on 2023-02-06 / Affiliate links / Images from Amazon Product Advertising API