Hi-Fi amplifier or multi-channel audio-video ?
If you are an audiophile, a two-channel stereo audio amplifier is better suited for listening to music.
However, if you also want to make the most of watching movies with multi-channel audio, then you should also consider purchasing an audio-video amplifier dedicated to your home theater.
It depends on whether you want to compose a pure two-channel stereo system, or whether you want to drive 5 or 7 or more speakers with a home cinema system.
A stereo amplifier is designed to accurately reproduce two-channel stereo audio, with excellent channel separation, far superior to that offered by home theater amplifiers.
So if listening to music is more important than video, then you'll no doubt have to opt for a quality stereo amplifier.
What level of performance can be achieved?
Technical specifications are always very important, as long as you do not try to reach their limits.
The power of the amplifier must be evaluated by choosing a model that offers a good reserve of power in Watts, which is suitable for the size of the room in which it will be placed.
Generally the advice is to choose an audio amplifier that has 40 watts per channel or more.
However, if you choose to buy in combination, or you already own, not very sensitive speakers, you should consider buying a more powerful stereo amplifier.
Contrary to what one might imagine, in fact, an audio amplifier that is much more powerful than the speakers can accept is in fact less dangerous than the reverse situation. In fact, a low-powered hi fi amplifier risks fragmenting the audio band too much and delivering all its power only in the high range, with the consequence of burning the tweeters of the audio drivers.
The bandwidth of hi fi amplifiers is usually oversized, as well as the level of distortion is always well controlled, especially in transistor models (solid state amplifiers).
The rise time, on the other hand, varies from one model to another. As an indication, you should know that a very high rise time is usually an indication of good musicality, because it well returns the essential passages in the musical signal.
The preamp section must also be well taken care of: the possibility of excluding any tone controls is a feature that seems indispensable to audiophiles ("direct" function), while the presence of a phono input (with RIAA preamplifier) to connect a turntable will make the happiness of vinyl lovers.
You need to evaluate the use you'll make of the amplifier right away, so that you can choose a model that has all the inputs you need to meet your connection needs.
The number of inputs in the preamp section can therefore be decisive in choosing a Hi Fi audio amplifier, to allow the connection of all the devices of your interest (CD player, DVD player, Network player, Blu-Ray, Audio DAC, etc.) without forgetting the possibility of connecting analog devices such as vinyl turntables, a tuner, a cassette recorder, a reel, MD, and so on).
The presence of a possible selector to connect an additional pair of loudspeakers allows you to play two listening areas in the same room: two rooms, two different rooms in the office, etc..
However, you should know that the available power, in this case, will be divided between the two pairs of speakers.
The remote control: do you need it or not?
The remote control for volume control is a very convenient accessory that is increasingly present in the equipment of an audio amplifier. It allows you to position the system at the correct distance and to adjust the listening level while sitting comfortably.
It is certainly not an essential or indispensable accessory, but it is certainly practical.
Often, in the case of a valve amplifier, this option is not available. It can be a precise design choice, to obtain a cleaner and more essential audio signal. Therefore, the absence of the remote control can be a strong point if you are looking for the highest possible audio quality.
In addition to the remote control that may be supplied, there are numerous universal programmable remote controls that can be used to control all the components that make up the Hi Fi system.
Why Choose a Separate Power Amplifier
Buying a separate preamplifier to combine with one or more power amplifiers is certainly a more expensive choice than buying an integrated amplifier (i.e. with a preamplification section included in the amplifier itself).
This choice is therefore aimed at those audiophiles who want to compose a Hi Fi audio chain with uncompromising performance and out of the ordinary.
The next question is: better a stereo power amp or mono blocks, or a dual mono ?
Power amplifiers generally do not have a volume control, as this is a function present in the preamplifier.
The internal architecture is designed around the power supply section, which is generously sized to meet the current demand.
The stereo power amplifiers have a common power supply for both channels, with a symmetrical structure of the power transistor banks (one for the right channel and one for the left channel).
These models can sometimes be bridge-mounted for twice the power amplification.
This function is usually present on amplifiers for professional use and is rarely present in high-fidelity power amplifiers.
Monoblocks are monophonic power amplifiers, each with its own chassis. Each of them amplifies a loudspeaker, independently. This allows the distance between the audio amplifier and the speakers to be reduced.
Dual-Mono Hi-Fi amplifiers are two monoblocs joined together in a single chassis, where the two amplifications are in fact completely separate and equipped with two distinct and independent power supply sections.
The hi fi amplifier classes
Sometimes the class of the hi fi amplifier is indicated (Class A, Class AB, Class B, Class D, Class H).
This feature indicates how the electronic design of the amplifier itself works.
- Class B or AB: is the most widespread. It offers excellent performance, both in terms of musicality and performance. The Pure Class A is appreciated by the most demanding audiophiles, as it reduces the distortion of very weak audio signals. Class A also produces little power and a lot of heat compared to Class AB Hi Fi amplifiers.
Class A+ consists in having the hi fi amplifier work in Class A up to a significant percentage of its rated power, and then switch to Class AB. In this case, it is said that the amplifier is highly polarized to Class A (as is the case with most transistor amplifiers produced by Xindak).
- Class D: are switching audio amplifiers that work in pulse width. This very special mode offers excellent performance (combined with very low heating). Their realization requires a design quality usually higher than that of other models, especially with regard to the selection of components. Class D is usually reserved for high power audio amplifiers, often used for professional purposes.
- Class H: This is a Class AB where the power supply voltage is modulated for very strong signals. It is mainly used for professional sound.