An audio system is mainly composed of two types of components: the speakers, which, as the name implies, have the task of diffusing the sound in the environment, and the power amplifiers , which serve to modulate the strength of the electrical signal that encloses the sound message. There are other parts that make up the system, for example the source (the CD or DVD player), however to obtain the best possible result in terms of sound quality it is absolutely essential that the speakers and amplifiers share some characteristics, and above all that they are compatible in terms of sound quality.
To choose an amplifier, you must first establish what kind of system you want to build. Music lovers mainly appreciate stereo sound since the recording standard of music tracks requires the use of only two channels.
By combining the signals of the two channels it is possible to create a realistic sound stage in which each component of the musical scene (voice and instruments) is positioned in a very specific point. But for even better positioning in space, useful for example with movies recorded with multi-channel encodings (Dolby Digital, DTS), you can choose a multi-channel amplifier.
Index
- Stereo amplifiers
- Power output
- TDH + N
- SNR
- Crosstalk
- Connections
- Other characteristics
- Multichannel amplifiers and receivers
- Amplifier: which one to buy
- Best budget stereo amplifier (under $ 400)
- Best mid-range stereo amplifier (under $ 800)
- Best high-end stereo amplifier (over € 800)
- Best receiver
Stereo amplifiers
The stereo amplifiers are characterized by the possibility of connecting two (or two pairs) of loudspeakers creating a right channel and a left. As we have already written, they are especially useful for listening to music CDs, DVDs, or even liquid music (via file). In fact, with the most modern models we can connect a smartphone via Bluetooth, or a USB key containing music tracks.
In addition, traditional amplifiers give the possibility to connect the speakers to multiple sources, making you choose from time to time which one to use at a given moment. They can also be used with movies, since even with a multi-channel source the sound is combined to be heard in stereo. Usually for the same price, a stereo amplifier offers superior audio quality compared to a multi-channel amplifier.
There are various types of stereo amplifiers, including tube amplifiers (the favorite of audiophiles) and solid state (the most common), which in turn are divided into classes. Without going into too much boring technicalities, the most popular amplifiers are in class AB , while in recent times very valid solutions are also spreading with a very low cost in class D and T which, thanks to an extremely simplified electronic part, allow to obtain a high sonic cleanliness and good output volume.
Usually experts recommend combining a class D or T amplifier with high sensitivity speakers (more than 90dB), in order to obtain high output volumes and good sound cleaning at the same time. Here are some definitions that can be useful in choosing a good amplifier .
Power output
We can simplify everything by saying that the output power is directly linked to the volume that the speakers will deliver. But as we have pointed out above, the final result is also linked to the speaker itself and its characteristics, including sensitivity . Don’t be fooled by the numbers of supermarket compacts: a power of 10W RMS already corresponds to a good volume with the vast majority of speakers, where with 100W you literally risk going crazy!
TDH + N
THD + N stands for Total Harmonic Distorsion + Noise , and is a measure that establishes how much the amplifier “colors” the signal as the volume increases. The higher the value, the lower the sound quality of the amplifier since it generates a higher level of distortion . The lower it is, the more the sound coming out of the amplifier will be similar to that coming from the source. It is clear, however, that it is the speaker itself, throughout the system, that has the greatest impact on the sound produced, so the numerical value can tell us very little if it is not combined with the result obtained with a particular speaker.
SNR
SNR literally means Signal to Noise Ratio , and defines the background noise produced by the electronics transferred to the speakers. Manufacturers aim to reduce any hiss and background noise as much as possible, so that it is inaudible even at very high listening volumes. In this case a high value indicates a better result, therefore a higher musical volume in the absence of background noise.
Crosstalk
The Crosstalk identifies what the right channel is independent from that of the left, and vice versa. Traditional amplifiers contain the electronics of both power amplifiers in the same casing, so it is possible that each of the channels is contaminated by the signals coming from the other. A low crosstalk value (careful, -100dB is lower than -60dB) is therefore the ideal situation, and translates into greater simplicity in distinguishing the precise position in space of one of the musical instruments present.
Connections
Of course, connections do not establish the quality of a product, but they make it more or less versatile. An amplifier that only has speaker connections or RCAs for sources forces you to purchase a traditional source, such as a CD or DVD Audio player. In fact, there are now several models that support the Bluetooth standard, integrate USB ports or even the Lightning connector for iPhone and iPad. It is clear that the connections available are indispensable when choosing the amplifier.
Other characteristics
If you are very attentive to the final quality of the sound coming out of your amplifier I also recommend that you look for two options: Pure Direct (or Source Direct, not all manufacturers call it the same), and Loudness .
These are two listening modes that are literally polar opposites: Pure Direct allows you to bypass most of the electronic components (for example the one to configure the high and low tones) in order to offer an output audio that is as clean as possible; while Loudness is a listening mode with exaggerated tones at the two extremes (highs and lows) in order to make the sound result more engaging (but at the same time false).
Finally, there are two important features to consider when purchasing an audio amplifier:
- Impedance: is an electrical quantity that measures the ease with which alternating current passes through an electrical circuit. When buying an amplifier it is good to check that the value supported by the speakers is compatible.
- Frequency response: humans can hear in optimal conditions a range of audio frequencies ranging from 20Hz (very low sounds) to 20,000 Hz (very high sounds). The amplifier must therefore try to cover the entire range of audible frequencies without strong attenuation, and it is even better if you go a little further.
Multichannel amplifiers and receivers
Naturally, all the considerations we have made so far for those devoted to stereo are valid for synto-amplifiers or multichannel amplifiers . The sound quality of a receiver is in fact based on the same technical characteristics, but as we have already said, the products are usually less “musical” for the same price.
But no worse, since in addition to being able to connect to the same source usually more than five channels, they are also much more versatile and can respond to different needs. Also designed especially for movies and cinematic audio, they can be connected to a television and manage its video streams.
Also in this case the choice must be made in consideration of the speakers you are going to connect: if our “speakers” are too pushed on the highs it is good to choose a softer amplifier with a warm sound, and vice versa.
There are also receivers that can connect from 5 to 9 channels , and there is also the possibility of connecting one or two LFE channels, for low frequencies, with as many subwoofers. The audio of the films is in fact more scenographic and less precise, and explosions, thunder, and bangs of all kinds are exaggerated thanks to the use of the subwoofer. Compatibility with various supports, a sector in rapid and constant evolution, should not be underestimated.
The receivers often offer digital outputs , because it is the most used type of connection for home audio systems. With just one connector it is possible to route the audio to a large number of channels, however to do this the system must be compatible with the format provided by the source.
Many movies use the Dolby Digital or DTS format, mainly with 5 channels plus 1 for the subwoofer (LTE), but there are also more advanced variants with a higher number of channels. If your goal is to watch a lot of movies, I recommend that you buy a receiver that has both supports, in order to always enjoy the highest possible audio quality.
A receiver amplifier is usually much more complex than a traditional stereo amplifier, and uses an advanced user interface to allow maximum customization of the options offered.
Some models also allow you to automatically configure the frequency equalization of each individual channel by means of a microphone supplied, which allows you to “listen” to the acoustic characteristics of the environment and choose the best settings. As is now the case with stereo amplifiers, many models are equipped with a remote control with which to manage all options even from a distance.
Amplifier: which one to buy
The low-end of traditional amplifiers consists of models starting at a price below 400 €. They are products that offer a much greater cleanliness than the compact mall (the stereos of the most popular brands, which you probably already owned when you were younger) and are characterized by a more than satisfactory audio quality for those who do not have many pretensions.
Best budget stereo amplifier (under $ 400)
Dynavox CS-PA1 (Class T)
It is a small amplifier slightly more powerful than the Sure, with an output power of 25 + 25 W and a frequency response of 20 Hz to 30 kHz. It’s also more versatile, with the ability to connect speakers to multiple different sources. Compared to the Sure it also gains tone controls and a connector for a pair of headphones. The outer casing remains extremely compact: 180 x 140 mm the surface, with a height limited to 65 mm and a weight of 2 kg. It can be combined with a TV in the living room or a traditional stereo.
Dynavox CS-PA1
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Fosi Audio BT30D (Class D)
A very interesting amplifier, to power small and easy to drive speakers. Very small in size, it is proposed with a 24V / 4.5A power supply and supports from 2 to 8 Ohm of impedance with a maximum power of 50W per channel (very optimistic). Its peculiarity is the support for Bluetooth 5.0 connectivity, in addition to the presence of a port for connecting an external subwoofer to expand the low frequencies. Five potentiometers are present: one for the general volume, two for the volume and cut-off frequency of the subwoofer, and the remaining two to manage high and low tones.
Fosi Audio BT30D Bluetooth 5.0 Stereo Audio Amplifier 2.1 Channels M …
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Auna CD708
The Auna CD708 is an extremely economical amplifier with low-end technical features that make it suitable for everyday home use. It is aimed at users who are not very demanding in terms of audio quality and built-in features, and has tones for bass, mids and highs to offer a balanced sound based on the needs of individual users. On the back of the system we have five inputs and an RCA output for radio receivers, cassette players and CD players. On the front instead there is a port for connecting external headphones in order to listen to music even at night.
AUNA AV2-CD708 – HiFi stereo, Audio amplifier, RMS power supply …
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Denon PMA-600NE
Denon’s entry-level model offers a power of 70 + 70W RMS into 4 Ohms. Thanks to the high current circuit it allows to obtain power combined with a high control, and the large capacity capacitor for the power supply circuit also helps. The amplifier integrates energy saving features that allow you to save on your electricity bill, such as the automatic shutdown function and the stand-by mode. It also supports Bluetooth and the remote control is included in the original equipment.
DENON PMA-600NE Integrated Amplifier, Silver
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Best mid-range stereo amplifier (under $ 800)
NAD C316BEE
The NAD C316BEE is an affordable stereo receiver often chosen by audio enthusiasts who want to spend the bare minimum for quality sound. It is characterized by its rather warm audio tone that manages to dampen the character of the most exuberant speakers with the two extremes, high and low, of the sound spectrum. It offers a power of 4W per channel, it is not very modern, but it remains one of the most popular models in this price range.
Graphite integrated NAD C316BEE stereo amplifier
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Marantz PM6007
Marantz PM6007 is the mid-range model of the famous manufacturer, a reference point for enthusiasts and audiophiles. The output power is 45 + 45 W RMS on an 8 Ohm impedance, and there is no shortage of digital inputs, the Phono MM for an external turntable, the output for headphones and the remote control. It is a model that allows you to start hearing music seriously and allows you to produce a powerful and high quality signal. Inside there is a massive toroidal transformer, and also a latest generation high resolution DAC (192kHz 24-bit, model AK4490).
Marantz PM 6007 Black
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Denon PMA-800
A great amplifier halfway between the budget models and the more powerful ones. The integrated amplifier has two power amps of 80W into 4 ohms each, and the AHC Advanced Hight Current single Push Pull power circuit offers sustained power for different types of loads. We also have a built-in high definition DAC (24-bit and 192kHz), as well as a wide range of inputs and outputs. Great for high sensitivity speakers.
DENON Pma-800 Amplifier, Silver
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Audiolab 6000A
Stereo amplifiers are usually large in size and come with several connectivity solutions for devices that you will probably never use. If, on the other hand, you are a lover of digital music, or you need a quality amplifier for external speakers to match your TV and you don’t want to compromise on cheaper compact solutions, then take a look at Audiolab 6000A . This amplifier can power two 50W channels with an impedance of 8 Ohms and is equipped with the Saber ES9018 chip with the ability to process audio up to 32-bit. You can connect it to the source via analog or digital (even via optical), and Bluetooth is also supported.
AUDIOLAB 6000A BLACK
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Best high-end stereo amplifier (over € 800)
Cambridge Audio CXA61
A refined and modern amplifier, with quality audio with clear British notes. The Cambridge Audio CXA61 is an integrated 60W per channel with class AB amplification, compatible with different types of connections both digital (Toslink and coaxial, or even USB), and analog (four RCA connectors and a 3.5mm jack are present) . There is no lack of Bluetooth support, through the aptX HD codec. Thanks to the DAC ESS Saber SE9010 K2M allows you to reproduce audio at very high resolution (32bit / 384kHz).
Cambridge Audio CXA61 Integrated Stereo Audio Amplifier – Bluetooth …
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Yamaha R-N803D
With a power of 100W per channel (at 8 Ohm), the Yamaha R-N803D amplifier offers the possibility to connect to DAB + radios with the guarantee of excellent audio quality based on the Top Art concept (Total Purity Audio Reproduction Technology). It can be connected via Wi-Fi and via Bluetooth, and has several outputs and inputs, including a USB and output for the subwoofer. There is also the Pure Direct mode, to bypass all controls and get the best possible cleaning.
Yamaha R-N803D 100W 2.0 Channel Stereo Black AV Receiver
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Denon PMA-1600NE
The Denon PMA-1600NE model is for refined palates, for those who do not accept compromises but still want to rely on an integrated solution (with amplifier and pre-amplifier included). It has a declared power of 140 + 140W into 4Ohm, 70 + 70 into 8Ohm, Phono MM / MC input for turntables and direct amplifiers. Two transformers with Leakage Canceling circuit, ultra selected components and excludable tone controls allow you to receive an extremely clean sound in all circumstances.
Denon PMA-1600NE Amplifier with Built-in DAC, 70 + 70 W RMS on 8 O …
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Marantz PM8006
Marantz PM8006 is another top notch amplifier designed for very demanding users. It is characterized by the output power supplied, equal to 70W with an impedance of 8 Ohms and weighs 12 kilograms, for a product that can offer a signal / noise ratio of 106dB. It can drive even very difficult speakers and has dedicated tone controls (here also for the mids), Power Amp Direct button and Source Direct, in order to have a musical reproduction that is as clean as possible and similar to what the artists wanted.
Marantz PM8006 2.0channel Wired Black audio amplifier
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Best receiver
Sony STR-DH190
The Sony STR-DH190 is a stereo (2.1) receiver that can be connected to four speakers (but playback is only available in pairs between systems A or B), with support for an external powered subwoofer. It has a Phono input for connecting to the turntable, but also more modern technologies such as Bluetooth to play music from your smartphone, or other compatible devices. It features an FM radio tuner with 30 preset stations, and also supports Hi-Res Audio. A good entry-level product, certainly among the most reliable.
Sony STR -DH190 Av Receiver, Black
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Yamaha R-N303 D
With the Yamaha R-N303 D you spend the right amount and get a good quality performance, through a product that not only allows you to connect to DAB and DAB + radio stations, but offers you many functions to enjoy music from the most disparate devices. It supports MusicCast technology to connect wirelessly to your smartphone or PC, and can also be managed via the app, from your smartphone. There is also support for Bluetooth and native support for various streaming services, such as Spotify, TIdal or Deezer. You can also connect it to your TV via digital cable.
Yamaha ARN303DBL Receiver, Black
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Denon DRA-800H
Another stereo receiver, designed not only for music reproduction, but also for movies and TV series. It supports DTS, DTS HD, Dolby Digital, Dolby Atmos, and also offers the ability to connect to FM and DAB / DAB + radio stations. All around a very powerful amplifier, with 100W per channel (two) at 8 Ohms and reduced distortion. This device can also connect via Wi-Fi to AirPlay 2, is equipped with Bluetooth connectivity, and offers an AKM 4458 DAC that allows you to play audio even at 768khz / 32bit resolution. There is clearly the Hi-Res Audio certification, for a product with undoubted sound quality.
DRA-800H
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Denon AVR-X1600H
If you want to set up a high-quality multi-channel system, I suggest the Denon AVR-X1600H , a receiver with modern features and the ability to power seven channels with 145W into 6 Ohms with discrete broadband power stages. It supports dual-band Wi-Fi, AirPlay and DLNA technologies and the Spotify Connect function, as well as the most widely used audio encodings in cinema. It is a complete receiver with support for internet radio, AM / FM and RDS, while on the connectivity front there is really everything: front USB input, 6 inputs and an HDMI 3D 2.0a output, support on all inputs of the HDCP 2.2 protocols and 4K Ultra HD HD60 resolution, also in HDR, and there is also the possibility of connecting up to two subwoofers.
AVR-X1600H
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Denon AVR-X2700H
The Denon AVR-X2700H is a good high-end receiver, capable of delivering a whopping 150W RMS per single channel to a total of seven speakers arranged around the room. It has support for Dolby HD, DTS HD, is compatible with the HEOS Multiroom standard and can connect to other devices either via Wi-Fi or via Bluetooth. There is also support for Dolby Atmos, for direct music streaming from applications such as Spotify, and we also have the ability to play music via AirPlay and multimedia content via Dlna. The HDMI outputs can also be connected to 8K TVs or 4K displays up to 120Hz.
