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Willie Greer - August 17, 2021
In terms of efficiency, you can’t go wrong with a Class D amplifier. However, a class D amp is more than just the letter; it’s also the sound quality it can help the rest of your system produce. It’s important to learn the inner workings of these amps to avoid wasting your money, which is what our sound engineers are here to do.
APCLE18001D
- Great heat dissipation
- Oversized wire coils
- MOSFET power supply
- Subsonic filter
R3400D
- Highly efficient
- 1 ohm impedance
- MOSFET amplifier
- Variable subsonic filter
BT20A
- Compact design
- Affordable price
- Bluetooth 5.0
- Advanced circuitry
Reviews of the Top Class D Amplifiers
BOSS Audio Systems R3400D
The Boss Audio Systems R3400D has thoroughly impressed our experts. This class D amp offers a very high power output of 3400 watts at 1 ohm, half that at 2 ohms, and 850 at 4 ohms.
As a class D amplifier, the R3400D is highly efficient and has a MOSFET power switch. MOSFET controls the output voltage. Boss Audio Systems allows you to strap two of these high-quality amplifiers together to double the amount of power needed for your passive speakers.
There is also a variable subsonic filter plus a variable low pass crossover to ensure the best performance from this amp.
What We Like
- Delivers Hi-Fi sound with great efficiency
- Variable low-pass crossover
- Variable subsonic filter
- Strapping capable
- Monoblock class D amplifier
- Indicator LEDs
- Input sensitivity selector
- Input gain control
- MOSFET power supply
- 1 ohm stable
What We Don’t Like
- Not a lot of internal noise filtering
- Works better strapped for better subwoofer output
Audiopipe APCLE18001D
The Audiopipe APCLE18001D may be a bit more expensive, but the extra cost is worth it, especially since it comes with a very efficient heat sink that helps with high-temperature dissipation. Overheating is a big problem with amps of all classes and not just class D amplifiers.
The Audiopipe amplifier comes with 3 different power output ratings depending on the impedance, and it comes with advanced circuitry protection. You won’t need to worry about the APCLE18001D because it is protected against short circuit possibilities, overload, thermal and low voltage.
With the class D amplifier is a variable bass boost plus a low pass filter and adjustable phase.
What We Like
- Pulse width modulated MOSFET
- 4-way circuitry protection
- Variable bass boost
- Brings excellent audio quality
- Sufficient maximum power
- 1-year manufacturer warranty
- LED indicators
- 3 power ratings
- Minimal harmonic distortion
What We Don’t Like
- The shipping process can be improved
- The amp takes a lot of power
Fosi Audio BT20A
Fosi Audio is known for its small amps. The compact size does not hinder the BT20A’s overall performance. It’s a powerful amp that allows for Hi-Fi sound without costing an arm and a leg.
The small Bluetooth amplifier adopts the latest 5.0 technology, which provides a stable and more reliable Bluetooth connection than before. There is no noise and only low distortion once the amp is connected to your devices.
The Foss Audio BT20A can power your passive speakers more than adequately with improved signal strength compared to other amps at the same level. As such, it can improve your home audio system and boost your listening experience.
What We Like
- Improved Hi-Fi home stereo sound
- Reliable Bluetooth connection
- One of the more affordable amps on the market today
- Compact size but powerful amp
- Advanced circuitry design
- 18-month warranty
- Low total harmonic distortion of 0.04%
- Treble and bass control
- 24V power supply
- Budget price
What We Don’t Like
- The power indicator is always on
- Small speaker wire holes
Hifonics ZRX1816.1D
Hifonics really brings Hi-Fi audio to the forefront with their class D amplifiers. Some of the key features of this particular amp include the illuminated logo badge that sets it apart from the rest and SPC (Simpatico Coil Design) and the HSMD (Hifonics Surface Mount Design).
Protection circuitry is one of the most important key features that our sound team looks for in the best class D amplifiers and even A/B amps. The Hifonics ZRX1816.1D has DC, short circuit, overload, and thermal protection for longevity and durability.
The cast aluminum heatsink will also do a great job in aiding heat dissipation.
What We Like
- Unique design with illuminated badge
- Short circuit, overload, thermal, and DC protection
- Cast aluminum heatsink
- Excellent car amplifier
- 1 ohm stable
- MOSFET power
- SPC and HSMD
- Monoblock Class D
- 1-year warranty
What We Don’t Like
- It could click if not installed right
- Bass frequencies can be improved
Fosi Audio BT30D
Fosi Audio has small and compact amps that are budget-friendly and a great addition to your home stereo passive speakers. Among the key features of the Fosi Audio BT30D is the Bluetooth 5.0 connection that is much more stable – up to 50 feet!
The Texas Instruments chip installed in this class D amp is also what gives it an extra efficiency boost. The large knobs on the front make it easy for users to control the treble and bass levels, even without a remote control.
The subwoofer levels plus frequency control are also available on the front control panel.
What We Like
- 24V power supply
- Small class D amplifier
- Excellent sound quality
- 2.1 channel power amp for subwoofer
- Small and compact design
- Bluetooth 5.0
- Easy controls on the front
- Low noise and harmonic distortion
What We Don’t Like
- Small wire holes
- No smart switching between Bluetooth and wire connection
Hifonics BG-1900.1D
You know a brand is excellent when it makes more than one appearance on our list of best class D amps. The Hifonics BG-1900.1D is considered an excellent Class D amplifier with Ultra-Fi MOSFETS for maximum efficiency.
The frequency response goes down to as low as 10 Hz and reaches as high as 500. To support the amazing sound quality and the power output, the BG-1900.1D has an efficient cooling system that will regulate the temperatures for longer playtime.
The stereo amplifier also features a beautiful design with the Hifonics badge clearly visible across the surface.
What We Like
- 1900-watt maximum power output
- Great frequency response
- Super D class technology amp
- Ultra-Fi MOSFET power supply
- Monoblock amps
- Cool aesthetics
- Highly efficient model
What We Don’t Like
- May exhibit very minimal distortion
- Not all people like the illuminating blue light
AIYIMA A07 TPA3255
The AIYMA A07 TPA3255 stereo amplifier is a great match for your passive speakers. This small stereo amp emits minimal noise and keeps cool with the heat management system.
The Hi-Fi integrated class D amplifier achieves the best sound quality and continues to provide reliable performance year after year. Whether it’s car amplifiers or home stereo amps, users want a simple design that’s easy to use. The small amp is very sturdily built and can keep your home speakers company for years to come.
You can connect your devices using the RCA or aux input and enjoy minimal harmonic distortion.
What We Like
- TPA3255 chip
- Digital audio amplifier
- Bridgeable
- Very low THD
- Hi-Fi integrated class D amplifier
- Excellent subwoofer output
- Mini power amplifier
- Keeps cool
- Efficient power
What We Don’t Like
- Can output max power for a very short time
- No LC filter
Kicker 46CXA8001
For car amplifiers, Kicker is an amazing brand. The 46CXA8001 is a car amplifier known for its key features. As one of the best class D amplifiers on our list, it delivers on efficiency, durability and cooling. Plus, the Kicker 46CXA8001 has 12 db variable crossovers, a variable bass boost, and a subsonic filter.
All of the above filters and crossovers can be controlled in this monoblock class D amp. The sound is amazing from this small amp, and it operates at 1 ohm stable, allowing you to integrate even more subs.
The horizontal mounting software is something new for these world-class amps to display the unit in style.
(Looking for an amplifier that offers more versatility? Why not get the top 5-channel amps listed here?)
What We Like
- 9V power supply from battery
- Fail-safe Integration Technology
- Noise rejection
- 1 ohm stable
- Horizontal mounting software
- Adjustable filters and crossovers
- Efficient and small
What We Don’t Like
- May draw a lot of power
- Controls are not easily accessible
Fosi Audio BL20C
Fosi Audio is a heavy-hitter for home speakers with the latest Bluetooth technology. Like most of their other units, the controls of the Fosi Audio BL20C are located right on the front panel. The bass, treble, and volume knobs are easy to turn and clearly labeled.
There is even a U-disk input available for portable amp use. The 24v power supply is enough to bring powerful sound and elevated overall performance to all speakers.
The small 2.1 amp is great for two speakers and one subwoofer, making it a great class D amp for your home system. Even high volume won’t result in any noise, thanks to the TDA7498E chip embedded in the amp.
What We Like
- Reliable performance
- Excellent power handling
- 24V power supply
- U-disk input
- Bluetooth 5.0 and RCA
- TDA7498E chip for efficiency
- Accurate sound
- USB input
- 2.1 channel mini amp
What We Don’t Like
- May emit a very low hum without sound
- Lacks SDPI output
Rockville dB15
Lastly, our team has included the Rockville dB15 monoblock class D car amplifier. The small amp comes with remote control and mounting screws to make installation easier. The peak power handling is what really blew our experts away. You can get a total of 6000 watts at peak or 1500 RMS power that’s certified by Dyno.
The Rockville amp also features a high-speed MOSFET power supply and adjustable crossovers. Low pass and subsonic filters are present in this power amp, as well as a phase control switch.
Your devices are protected from under and over-voltage to ensure reliable performance.
What We Like
- Comes with a remote control
- Reliable class D amp
- Very high and certified power handling
- MOSFET power supply
- Low total harmonic distortion
- More efficiency than class A/B amps
- High-quality sound
What We Don’t Like
- No internal fan
- May go into protection mode automatically
Class D Amplifier Buyer’s Guide
The best class D amplifier will go well with your home system or power your car audio. Power is one of the key features many people consider, but other things include sound quality, the class of the amp, input sensitivity, and many functions such as rapid switching. Let’s take a look at the most important ones as defined by our experts.
Size and Weight
Yes, you need the amp to be the right size and designed for your setup. Most of the ones our audio engineers suggest are very small and won’t take up much space. Many of the models also come with a remote control, which can help with your adjustments.
While the size will contribute to the weight of your class D amplifier, you should also think about the housing. The housing is the overall structure and materials used to build the amp. Our sonic experts say that the build will also impact the sound and integrity at high maximum output. Aluminum is a great material as it is sturdy yet lightweight.
As you will read later on in our article, the type of amp will also have a significant influence over the size and weight of your amplifier. We’ll briefly mention it here.
Class Ds are your best bet if you have a small setup and don’t have a lot of space to offer. Because they are efficient, they don’t need to include space for a large heat sink or other heat dissipating components. This fact can successfully minimize their footprint by up to half!
If size and weight are not an issue, then our team suggests class A/B amplifiers. Again, it also depends on your system. Are you looking for a car amp or a home theater one? Your answer will also determine the type of amp and its size.
Power
Power is also a very significant consideration. Different impedance levels, measured in ohms, will impact the total power handling of your system. Much like speakers, the power rating in amps also comes in two categories – peak and RMS power.
The RMS is the continuous power output from the amplifier and is what manufacturers tend to list in the product description. In general, the higher the ohm or impedance, the lower the wattage output. Common impedance ratings you can find in these class D units include 1, 2, or 4-ohm stable models. The ohm stable rating is usually reserved for subwoofers.
The higher the power handling, the more power you will get and the louder the sound. Unfortunately, not all D class amps are built the same, and many that are capable of a ton of power do not reflect the same performance in efficiency. This is why our team members recommend MOSFET power, which is designed to handle a ton of power.
Not only does MOSFET handle significant power, but it also helps with cooling. Amps that feature MOSFET or a high power output usually have in-built heat sinks as well to help dissipate the high temperatures. Our team says this is a must because your amp won’t last long without sufficient airflow and cooling.
Speaking of lasting long, our experts also remind our readers to look for protection circuitry that goes hand-in-hand with power handling. You can find 3 or 4-way protection circuitry in D class amplifiers that guard against electrical hazards. For example, an amp can feature overvoltage, under-voltage, short circuit, and thermal protection.
Even the features will help protect your device from the power output. Many of the models our team members have suggested include a power adapter. A power adapter is different from a regular charger as it is designed to convert AC into the correct voltage for your DC outlet. If you have a DC outlet, you need a power adapter.
Frequency Response
Although the frequency response is the main focus of this section, our audio engineers will take this opportunity to address other factors that affect sound quality.
What is the frequency response? It is the signal range that your amp recognizes and can effectively send to your speakers. To put it simply, our experts say that a wider frequency range will guarantee more audible notes from the entire audio spectrum.
The human audible range is from 20Hz to 20kHz [1]. All you really need is for your class D amp to cover this range. However, while we can’t hear anything above or below this sound range, we can certainly feel it, so there is no harm in exceeding the above scope.
You may find it difficult to reach as high or as low as you would like, but our team says a great way to mediate the issue is to focus on the type of sound you want. For example, if you are a bass head, look for ones that have a lower frequency range.
Most of the units our experts have included on the list can perform accordingly, even the small Bluetooth amplifier units from Fosi Audio.
The THD, or total harmonic distortion, is another one of the key features our experts looked at in the best class D amp. The THD is important because it works with the frequency range to bring the best audio quality directly to your ears. You want the THD to be as low as possible. Preferably, our team says to look for THD below 1% at the very least. Our experts recommend 0.04 to 0.05% as the most optimal.
Then comes the signal/noise ratio, which also greatly impacts the sound quality. This measurement pertains to signal strength with minimal noise. This rating is much like speaker sensitivity, and it is measured in dB, or decibels. You want the noise/ratio to be as high as possible. Our team recommends at least 90 dB amplifiers. Of course, if you can find a higher dB over 100, then that’s even better.
Connectivity Options
How the class D power amp integrates into your system is also another key feature. The best class D options will offer a variety of connectivity options ranging from wired to wireless. Which type is best for you? Our experts say it works the best with the rest of your system, the setup you want, and the type of devices you wish to connect.
Bluetooth is a very common wireless connection featured in amps. Make sure you look at the version of Bluetooth technology embedded in the device. Most of the ones that do offer Bluetooth on our professionally curated list have Bluetooth 5.0.
Bluetooth 5.0 is the most updated version of Bluetooth that offers more reliability and stability over greater distances. Bluetooth was previously stable up to 30 to 33 feet, but the upgraded 5.0 can provide a strong connection at around 50!
Of course, aside from distance, the sound quality provided by newer versions of Bluetooth will also be much improved.
As far as wired connectivity goes, we would suggest looking for amplifiers that incorporate USB, AUX, optical, plus coaxial, and anything else you may need. The connection will greatly depend on the compatibility with the rest of your sound system.
One of the pros of wired connectivity is reliability. You won’t have to worry about losing signal over greater distances or the signal dropping out. But there are also downsides to using wires, such as the placement flexibility. You will end up with a much more stationary and permanent system.
While wireless connections do offer a greater variety of placement options and a clean setup, you need to make sure the devices both feature the same upgraded Bluetooth versions to really enjoy it. Keep in mind that amplifiers can easily offer both forms of connections, which means you can easily get the placement flexibility offered by wireless technology but the stability provided by wired connections.
Another consideration for the setup and connections is the remote control. Does your choice of amp come with a remote control with many functions, or will most of the settings need to be done with the onboard control panel? Our team always recommends one with a remote control is possible.
(Lacks the right connectivity? Well, you can still hook up your amplifier without the RCA jacks using this guide)
Input
Our team mentioned the inputs required for amps, but the key is to look at which specific ones you need. Take a look at your car sound system or home speakers to determine the ones to want.
You also want to make sure the inputs are easily accessible. We have included a model with side mounts that is unique and allows for a better display of the amp as well as its inputs.
What is a Class D Amplifier?
In short, a class D amplifier is one that’s highly efficient, more so than the other classes, which we will get to in a second. Although it has much better efficiency, our experts say the fidelity will suffer.
Class Ds work with DC currents, which is why many of them require power adapters. A lot of them have MOSFETs because of the high power output.
Strangely, the D classes are not digital amps despite the efficiency factor. They run on analog circuits and use rapidly switching transistors. Going back to what our team mentioned about the fidelity, it makes the class D technology much less desired by audiophiles.
Members of our team still prefer it to other amps for efficiency and build, but most of our professional systems are set up with class A, B, or hybrid class A/B amps.
However, most casual listeners opt for class D units thanks to the smaller and more compact profile plus the improved heat management systems. Now let’s look at how the class Ds compared to other amp classes.
Class D Amps vs Other Amp Classes
With amps, it’s unfortunately a sacrifice between high-fidelity sound or efficiency, although class ABs do best at combining both. We hope that future technological advancements will yield more results. In the meantime, let’s start with the class A amp.
Class A amps are designed to run at full capacity, and this is regardless of whether or not there is a signal. This is detrimental to the heat managing system because, without a signal, the power turns into heat. This means that class A amps are among the hottest in performance. The class A amps will amplify both negative and positive signals, which further adds to the heat.
The efficiency levels of Class A amps are shockingly low and barely come close to our team’s standard. You’re looking at 75% power loss, with only 25% of the amp operating at full efficiency. In other words, try not to select class A amps if you can help it. Class As are known as high heat producers, but they also offer high fidelity, which brings us back to the point that it’s commonly a toss-up between the two.
In fact, class As bring amazing distortion-free and linear audio that you may not obtain from other classes. However, they are rare, and if you are looking for an amp for your car audio system, look elsewhere because you won’t find class As.
Class As are a far cry from the efficiency D class amps offer, which makes this a knockout round in favor of class Ds if you aren’t a professional audiophile looking to customize an amazing high-fidelity system.
Then we move onto the class Bs, which have a push-pull setup. Instead of just 1 transistor, you will find 2 in class Bs. You have dedicated transistors for positive and negative signals, which means there is less of a load for them to bear.
This also translates into lower heat generation compared to their class A counterparts. Because each transistor takes turns, it’s much more efficient but also results in lower fidelity.
Unfortunately, the class B amps are not the solution to efficiency because they will produce what’s called a crossover distortion. This happens when the transistors switch on and off. The distortion can be so noticeable that manufacturers prefer not to manufacture strictly class B amps.
Since you won’t find many singularly class B amps on the market, class D also takes the cake in comparison due to its climbing popularity and efficiency plus cool operation.
Lastly, we have the combined efforts of class A and B amps, which bring high efficiency and high fidelity to the table – but will it be enough to out-class the D’s?
The class AB amps also have two transistors, but unlike what we see in the Bs, class ABs don’t turn them off right when the other comes on, and they are on more than half of the time.
The result is a great reduction in the crossover distortion that is very prominent in the class Bs. This fact places class AB amplifiers closer to the level of class Ds. With the competitor within reach, ABs ramp up their game with their wide availability. As we said, the individual A and B amps are not commonly seen, but ABs are about as average as class Ds on the market.
As for the efficiency, Class AB amplifiers operate at roughly 70-80%, which is quite impressive. Since the crossover distortion is also significantly lower, we can see why the ABs are an excellent hybrid between the previous two classes. Home theater and stereo amps are largely AB.
Class AB is on par with class Ds in terms of accuracy, but our expert audio team still suggests Class D amplifiers in terms of efficiency and heat dissipation. Of course, it depends on where you intend to install it. For home systems, class A/B are excellent choices.
Advantages of a Class D Amp
Our team has been touching on the advantages of a D class amp throughout the amp sections. To help you have a condensed view of just how great the class Ds are, our experts will compile them in one easy-to-read section.
First of all, the efficiency of class Ds is unmatched, even by the coveted ABs. The efficiency rating is up to 90%, which is the most we can expect as of now. As you can see from the figures above, the class D units have the AB beat.
Since they are so efficient, class D amplifiers also have a smaller footprint than all the other classes available. You know technology is running at optimal levels if they do it without generating much heat.
Laptops are a great example of this concept. You will hear fan noise and feel the high temperatures emanating from your laptop when it’s struggling.
Because of their efficiency, the class D units do not need overly large heat sinks that take up more space, which is what contributes to the reduced footprint. Efficiency also equals longer battery life if you’re looking at portable amps. Most class D models are also affordable, which wins extra bonus points with us and consumers alike.
It’s very possible that manufacturers will not try to improve on the class Ds in order to balance fidelity with the efficiency. As of now, these amps are very popular in cases where the audio fidelity is not as required, such as with PA speakers.
Should you pick class Ds over the rest all the time? No. Your choice will be greatly affected by personal preference and the type of setup you have and want. As said above, those without a lot of space may not have the freedom to choose the type of amp. Home theater amps are largely A/B, and car amps are very commonly D.
FAQ
Are Class D amplifiers any good?
Yes, class D amplifiers are good. In fact, they are arguably one of the best classes for amplifiers out there. They are the epitome of efficiency in terms of amps, operating at about 90% efficiency, which is the best manufacturers can offer at the moment.
Do Class D amps sound better?
No, class D amps don’t sound better. They are the ones with the highest efficiency level, but it does come at a cost, the cost of fidelity. For the most accurate sound, you need a class A amp, which is not efficient at all, expensive, and rare.
Are Class D amps good for subs?
No, class D amps are not good for subs. They can function, but our sonic experts would recommend class AB amps for subwoofers. Ds don’t do well and are a little slow for quick bass, but class ABs will surprise you with their performance.
Our Top Pick For a Class D Amplifier:
BOSS Audio Systems R3400D
Our expert team’s top suggestion for the best class D amplifier is the R3400D from BOSS Audio Systems. It’s named this way for a reason, as 3400 is the max output at 1 ohm stable. It’s a D class amplifier that is highly efficient in its performance, doesn’t take up much space, and runs cool.
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