Comparison JBL VMA1240 vs Atoll IN100SE

— Concert. Professional amplifiers designed to work at concerts and other similar events. Their main external difference from home models is rack mounting; for almost all concert models, the mounting size is indicated in the characteristics (see below). In terms of performance, the main difference is the high power, in some models exceeding 1000 watts per channel even at 8 ohm load. You can also note a rather restrained design — where such a technique is used, the appearance is far from being of paramount importance.

— Informational. Amplifiers designed for use in public address systems — at stations, airports, shopping centers, etc. One of the features of this application is that passive loudspeakers can be located at a great distance from the amplifier — tens or even hundreds of metres. The standard way to ensure signal transmission over such a distance is to use transformers at the output of the amplifier and at the inputs of the loudspeakers. Such a "transformer" connection can be carried out according to the standards 100/70 V and 50/25 V; in fact, the presence of at least one type of output is mandatory for power amplifiers and integrated amplifiers (see "Type") for this purpose. However, preamplifiers can also be produced for information. Also note that some data models support only one audio channel; and multi-channel often provide the ability to quickly turn...on and off individual channels — this allows you to organize broadcasting in separate zones.

— Concert / informational. Devices that combine the capabilities of the two types of amplifiers mentioned in the name (for more details on each, see above). Almost all are rack-mounted (among purely informational models this is less common). They can also be single-channel, and there are quite a few such solutions.

Most modern amplifiers have toroidal transformers - with a toroid-shaped core, in other words, a donut. This type is considered optimal for amplifiers of any level up to Hi-End: it creates a minimum of "extra" electromagnetic radiation and, accordingly, interference. Some time ago, E-core transformers were also widely used, but they are considered obsolete and are becoming less common today.

The total capacitance of the capacitors installed in the power supply of the amplifier. Usually, for ordinary lovers of high-quality sound, this indicator is not practically significant: the capacitance is selected in such a way as to optimally (or at least minimally) match the characteristics of the amplifier. However, for demanding audiophiles who pay attention to the smallest details of audio system components, capacitors are also often of interest.

The fact is that they are an important part of the rectifier circuit — they smooth out current fluctuations that arise both due to the imperfection of the rectifiers themselves and due to various external factors. Knowing the total capacitance of the capacitors, one can also evaluate the efficiency of their work: the higher this indicator, the more stable the power supply will work and the lower the likelihood of sound distortion due to its fault. There are special formulas that allow you to derive the optimal capacitance of capacitors depending on the type, power and other parameters of the amplifier; they can be found in specialized sources.

The maximum number of channels the amplifier can handle. The choice for this parameter depends primarily on the intended format of using the device.

Most modern amplifiers have two channels for normal stereo sound, which is enough for listening to music or radio programs. There are also models designed for multi-channel "surround" sound, but they are much less common. This is due to the fact that such sound is most often used as an accompaniment to high-quality video — and therefore a home theater receiver is usually used for processing, rather than a separate audio amplifier.

Among the top-class models, there may be single-channel amplifiers — they provide maximum opportunities for fine-tuning the sound, but you have to purchase several such devices, one per channel. Another specific variety is amplifiers designed to add a certain number of channels to those already available; the most popular of these options is 3-channel, capable of turning an existing stereo system into a multi-channel one.

The range of audio frequencies that the amplifier is capable of handling. The wider this range, the more complete the overall picture of the sound, the less likely it is that too high or low frequencies will be “cut off” by the output amplifier. However, note that the range of sound audible to a person is on average from 16 Hz to 20 kHz; There are some deviations from this norm, but they are small. At the same time, modern Hi-Fi and Hi-End technology can have a much wider range — most often it is a kind of "side effect" of high-end circuits. Some manufacturers may use this property for promotional purposes, but it does not carry practical value in itself.

Note that even within the audible range it does not always make sense to chase the maximum coverage. It is worth, for example, to take into account that the actually audible sound cannot be better than the speakers are capable of giving out; therefore, for a speaker system with a lower threshold of, say, 70 Hz, there is no need to look for an amplifier with this figure of 16 Hz. Also, do not forget that a wide frequency range in itself does not absolutely guarantee high sound quality — it is associated with a huge number of other factors.

The nominal sound power output by the amplifier per channel when operating with a load having a dynamic resistance (impedance) of 8 ohms. In our catalog, this parameter is indicated for the mode when all channels of the amplifier work under load (see "Number of channels"); in the presence of unused channels, the rated power may be slightly higher, but this mode cannot be called standard.

Rated power can be simply described as the highest output signal power at which the amplifier is able to work stably for a long time (at least an hour) without negative consequences. These are average figures, because in fact, the audio signal is by definition unstable, and individual level jumps can significantly exceed the rated power. However, it is she who is the main basis for assessing the overall loudness of the sound.

This indicator also determines which speakers can be connected to the amplifier: their rated power should not be lower than that of the amplifier.

According to the laws of electrodynamics, with different dynamic load resistance, the output power of the amplifier will also be different. In modern speakers, the standard values \u200b\u200bare 8, 6, 4 and 2 Ohms, and power levels are indicated for them.

The nominal sound power output by the amplifier per channel when a load with a dynamic resistance (impedance) of 4 ohms is connected to it. See Power per Channel (8Ω) for more information on power rating and its relationship to impedance.

Rated amplifier power output per channel when connecting acoustics according to the 70/100 V standard.

This standard is used to communicate with high-impedance loudspeakers located at a great distance from the power amplifier — in particular, in public address systems and emergency announcements. Actually, most models with 70/100 V outputs refer to information or concert-information amplifiers (see "Intended use").

See "Power per channel (8Ω)" for details on power rating.

In itself, the signal-to-noise ratio is the ratio of the level of pure sound produced by the amplifier to the level of extraneous noise that occurs during its operation. This parameter is the main indicator of the overall sound quality — and very clear, because. its measurement takes into account almost all the noise that affects the sound in normal operating conditions. A level of 70 – 80 dB in modern amplifiers can be considered acceptable, 80 – 90 dB is not bad, and for advanced audiophile-class devices, a signal-to-noise ratio of at least 100 dB is considered mandatory.

If the specifications do not specify for which output the signal-to-noise ratio is indicated, it usually means its value for the linear input (see "RCA (par)"). This is quite enough to evaluate the quality of the device for this parameter. However, some manufacturers indicate it for other inputs — Main, Phono; see below for more on this.