Comparison Atoll IN50SE vs Atoll IN30

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 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 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.

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.

The sensitivity and dynamic impedance of the amplifier when a signal is applied to the RCA line input.

Under the sensitivity of any input (except optical) is meant the lowest signal voltage at this input, at which the amplifier is able to provide normal nominal power values (see "Power per channel (8Ω)"). This parameter determines, first of all, the requirements for the signal source. On the one hand, the voltage provided by this source must not be lower than the input sensitivity of the amplifier, otherwise the latter simply will not give the claimed characteristics. However, a significant excess in voltage should not be allowed, otherwise the sound will begin to be distorted. More detailed recommendations on choosing an amplifier by sensitivity are described in special sources.

For any input other than optical, it is believed that the higher this indicator, the less distortion the amplifier introduces into the signal. The minimum level of input impedance in modern models is considered to be 10 kOhm, and in high-end devices it can reach several hundred kOhm.

The number of line inputs in the amplifier design using the RCA interface. Unlike the Main input (see above), which can work with the same connectors, when connected to a linear RCA, the signal goes through all the stages of processing provided for in the amplifier — for example, adjusting the balance or frequencies (see "Adjustments"), etc. .P.

See “Amplifier Input (Main)” for details on the connector itself. Here we note that when using RCA as a linear interface, a pair of such connectors is considered one input. This is due to the fact that only one channel can be transmitted over one coaxial cable, so a pair is needed to work with stereo sound.

The number of signal inputs (of any type) determines how many signal sources can be simultaneously connected to the amplifier. Accordingly, it is worth choosing a model according to the number of inputs, taking into account the expected number of such sources: after all, it is easier to connect them all and select them through the amplifier’s remote control or control panel than to fiddle with reconnecting every time.

The number of REC outputs in the design of the amplifier. This output is a kind of line interface designed to output sound to a recording device; one of its features is a constant signal level. Since RCA connectors are usually used for connection (see “Amplifier Input (Main)”), a pair of connectors is counted as one REC output — this is the only way to ensure stereo sound transmission.

— Display. The presence of a display on the front panel of the amplifier. Such displays may have a different design and size, but they are all used to display service information: operating mode, selected signal source, special notifications, overload messages, errors, etc. This provides additional ease of use.

— Indicators. In this case, it means that there are indicators on the front panel that indicate the currently used signal source. Usually they look like a row of light bulbs with the appropriate signatures — "Phono", "CD", "Tuner", "AUX", etc. Such pointers are not as versatile as the display, but they are still very convenient.

— Arrow indicators. Presence on the front panel of indicators in the form of scales with arrows. Usually, such indicators are designed to display the peak level of the output signal. They make it easy to track overloads, and many users find this option more convenient and visual than displays. In addition, the arrow scales give the amplifier a stylish appearance, and, unlike the same displays, do not have complex electronics that can distort the sound. However, this category also includes other types of indicators with scales; some of them may not use an arrow, but other indicators (for example, light ones).

— Regulators behind a hidden panel. The presence of a cover on the front panel that hides the controls of the amplifier. Many models are e...quipped with additional controls on the front panel; they can be used to adjust both the sound — volume, bass / treble, balance, etc. — and other operation parameters (for example, selecting a signal source or switching between the main and additional speakers). Sometimes these controls (as well as the front panel inputs) are provided with a cover, usually for aesthetic reasons. an abundance of small elements would give the device a sloppy appearance. The cover can also perform protective functions — for example, it reduces the amount of dust that enters the connectors.

— Input audio jack. The presence on the front panel of an input for connecting an audio signal — usually linear, in analogue format. On the one hand, such an input greatly simplifies work with signal sources that need to be connected only occasionally and for a short time — for example, MP3 players: the front panel is always in sight, while getting to the connectors on the back is sometimes very difficult. On the other hand, usually the role of the front audio jack is played by AUX IN with a 3.5 mm mini-Jack jack. This connector is not used among the main inputs, but it is quite popular in portable electronics, in particular, the players already mentioned. Some models may have a pair of RCA jacks on the front panel (see "RCA (pair)"), but this option is less common.

— Headphone output. Headphone output on the front panel of the amplifier. Headphones are portable devices, and on average you have to reconnect them significantly more often than most other components of the audio system; the output located on the front panel greatly simplifies the process.

— Bass adjustment. The presence in the amplifier of a separate low-frequency level control, in other words, bass volume. The ratio of low and high frequencies largely determines the overall picture of the sound; the optimal options for this ratio for different cases will be different, and they depend on a number of factors — from the type of audio being played to the personal tastes of the listener. Anyway, the bass control provides an additional opportunity to fine-tune the sound of the entire system. It is often combined with a treble control (see below); in fact, this combination is the simplest version of the equalizer.

— Treble adjustment. The presence in the amplifier of a separate volume control for high frequencies. The meaning of this function is completely similar to the bass control described above, only it works with a different frequency band.

— Balance adjustment. The presence in the amplifier of adjusting the balance between the channels. This setting is used in stereo sound: by changing the position of the knob, you can increase the volume for one channel and decrease it for another. Due to this, the conditional centre of the perceived sound shifts towards the speaker that sounds louder. This feature can be very useful for correcting the sound stage — for example, if the speakers have different sensitivity, badly placed, or the signal itse...lf is not properly balanced. At the same time, the balance controller introduces additional elements into the design, which increases the likelihood of interference. And therefore, in top-class amplifiers, it may not be provided at all.

— Adjustment of input sensitivity. Ability to change the input sensitivity of the amplifier; For details on this parameter, see "Input Sensitivity (Line Input)". Also note here that the adjustment itself can be useful when working with several sound sources: it allows you to easily reconfigure the amplifier for each of these sources in order to provide the desired output power level and at the same time avoid distortion.

— Level adjustment. The presence in the amplifier of its own level control, in other words, a system that allows you to change the volume of the sound (by changing the actual output power). In modern home amplifiers (see above), this adjustment is common to all channels, and it is responsible for the actual volume; sometimes using the control on the amplifier is more convenient than on another component of the audio system. But in concert models, each channel, usually, is equipped with its own regulator, thanks to which there are many opportunities for fine-tuning the sound to a specific situation.

— Loudness. This function allows you to adjust the tone of the sound at a low volume. Its necessity is connected with the fact that the human ear perceives a quiet sound differently than a loud one; because of this, even high-quality sound at low volume will seem “blurry”, not clear enough. Loudness corrects this by boosting certain frequencies. Usually this mode is enabled by the user at will.