Comparison Yamaha A-S301 vs Yamaha A-S300

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.

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.

signal-to-noise ratio when the amplifier is driven through the Phono input. This interface is for connecting turntables; its features are described in the “Inputs” section below, and for the meaning of any signal-to-noise ratio, see the corresponding section above.

The damping factor describes the quality of interaction between the amplifier and the speaker system connected to it.

Due to the design features, any speaker is prone to the occurrence of so-called parasitic oscillations — oscillations that continue after the main impulse from the amplifier has ceased (similar to how a string continues to vibrate after a pluck). This phenomenon has a negative effect on sound quality, and manufacturers use various means to reduce it to an absolute minimum; suppression of parasitic oscillations is called damping.

The most effective type of damping is electrical, by reducing the output impedance of the amplifier. The lower this resistance, the better the amplifier keeps the speakers from unnecessary vibrations. To evaluate this effect, they introduced the concept of “damping factor” (damping factor) — the ratio of the load resistance (impedance) to the output resistance of the amplifier. The minimum value of such a coefficient for Hi-Fi class equipment is 20; indicators at the level of 100 – 120 can be called good, and among the Hi-End segment there are numbers of the order of several thousand.

At the same time, it is worth noting that when increasing to three-digit numbers, the original meaning of this parameter is, in fact, lost, and other points appear. The most important of them from a practical point of view is that models with a high damping factor are very demanding on the quality of the connection to t...he speakers — the high resistance of cables and connectors can negate the damping properties of the amplifier itself. There are other nuances associated with this indicator (in particular, recommendations for choosing an amplifier and speakers for each other); they are described in detail in specialized sources.

This indicator describes the amount of non-linear distortion introduced by the amplifier into the processed signal. Such distortions are not necessarily perceived as extraneous noise, but they degrade the quality of the sound anyway — for example, they can make it more deaf. It is almost impossible to avoid them, but it can be reduced to levels inaudible to the human ear.

As a result, the harmonic distortion factor (harmonics) is one of the main parameters describing the overall sound quality in Hi-Fi and Hi-End amplifiers. The lower it is, the clearer the sound. Hundredths of a percent are considered a good indicator for modern amplifiers, thousandths and below are excellent. The exceptions are tube and hybrid models, for which rather high harmonic coefficients are allowed; see "Element base" for more details.

— Euroblock. Analogue audio input (usually line level) using a Euroblock connector. This connector, used mainly in professional audio equipment, is remarkable in that it is attached to the wire using terminals. This is extremely convenient when working with stripped wires (which is often required in professional applications): screwing such a wire to the plug once and connecting / disconnecting the plug to the Euroblock connector is much easier than constantly unscrewing / screwing the terminals. In addition, such a connection is often made balanced (see "XLR (balanced)" below). Inputs of this type are found mainly in information and information-concert amplifiers (see above).

— Phono. Dedicated input for connecting to the amplifier turntables; often has a suffix indicating the type of cartridge that is compatible, such as "Phono MM" or "Phono MM/MC" (see "Advanced — Phono Stage" for details). Despite the proliferation of digital formats, these players are still highly regarded by audiophiles for their high quality and fidelity, and are often used in premium audio systems. However, connecting a "turntable" has its own characteristics — in particular, it requires a phono stage (for more details, see ibid.) — and standard inputs are unsuitable for this purpose. Therefore, a Phono jack is a must if you want to connect your turntable directly, without an external phono stage.

— USB B. The USB interface is widely used in com...puter technology for various peripherals. The presence of a type B input means that the amplifier can be connected to a computer as an external controlled device (slave). Most often, with this connection, it is used as an external sound card or audio interface — this provides higher sound quality and more extensive options for its settings than most built-in sound cards, even expensive ones. However, the matter is not limited to this: in some models, via USB type B, you can update the firmware or change the special parameters of the amplifier.

— Coaxial S / P-DIF. Digital audio input, a variation of the S/P-DIF interface based on a conventional electrical signal (the second variation, optical, is described below). Usually uses a common RCA connector, known as a "tulip", but has rather strict cable requirements. The bandwidth of any version of S / P-DIF is quite sufficient even for high-quality multi-channel sound, and the coaxial version itself is simpler, cheaper and more reliable than the optical one, but more susceptible to interference.

— Optical. Input for transmitting digital sound using light signals, via TOSLINK fiber optic cable; one of the versions of the S/P-DIF standard. The main advantage of optical fiber over traditional electrical cables is complete insensitivity to electrical interference; at the same time, it is more expensive and requires rather careful handling (in particular, it does not tolerate sharp bends).

— Balanced digital ( AES/EBU). The AES/EBU interface is used in the professional field to transmit audio in digital format. It can use several connection types; in this case, it means transmission over the so-called balanced line using an XLR connector. Both the principle of balanced connection and the connector itself are described in detail in the “XLR (balanced)” section below — however, in the case of AES / EBU, we are talking about a digital signal, not an analogue signal.

— COM port ( RS-232). A connector used to control the amplifier from a computer. Through it, you can change the settings, incl. and quite thin, and in some models even update the firmware. Usually, for such purposes, special software is required, which can be supplied with the amplifier.

— Control input (IR). Connector for connecting an external infrared remote control receiver. When properly placed, such a receiver will allow you to use the remote control even in places where the signal from the remote control cannot reach the main (built-in) sensor — for example, in another room. For such purposes, not only sensors can be used as a separate device, but also system components that are compatible with the remote control — for example, players or tuners.

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.

— 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.