Comparison FiiO A1 vs FiiO Mont Blanc E12

The nominal impedance (impedance) of the headphones for which the amplifier was originally designed.

Modern headphones can have different impedance. In particular, among the most popular options are 16 ohms and 32 ohms, and advanced models have values from 300 ohms and even from 600 ohms. High-resistance is considered to be "ears" with a resistance of 100 ohms. These characteristics improve the purity of the sound, but require increased signal strength — and built-in amplifiers in handheld devices, computer audio cards, etc. usually have difficulty with this. Therefore, external amplifiers are often used for this very purpose — to effectively "shake" high-end headphones with high impedance. For the same reason, some of these amplifiers are not compatible with low-impedance “ears”: there are many devices that require headphones with an impedance of at least 32 ohms, or even higher, and in some models the lower limit of the operating range can reach 100 ohms. As for the maximum resistance, the range of its values is very impressive — from 32 ohms in relatively simple portable "amps" to thousands and even tens of thousands of ohms in high-end stationary models.

Anyway, you should not violate the manufacturer's recommendations for headphone impedance. If the resistance of the “ears” is too low, at best, the sound will be s...ubject to noticeable distortion, at worst, equipment failure and even fire may occur. Too high resistance, in turn, not only reduces the volume, but also worsens the frequency response.

Rated headphone output(s) provided by the amplifier.

Rated is the highest average power that the device is capable of delivering for a long time without overloads; individual “jumps” of the signal may have a higher level, but this indicator is the main one. The sound volume of the headphones connected to the device directly depends on it: with the same characteristics of the “ears” (primarily sensitivity), the high output power of the amplifier allows for a higher sound pressure level.

There are special formulas and tables that allow you to calculate the minimum power level required to achieve a particular volume. For example, to achieve 95 dB (the minimum required level for listening to music in silence at a satisfactory volume), headphones with a sensitivity of 100 dB will need 0.32 mW, for 105 dB (recommended level for powerful sound like rock concerts) — 3, 16 mW, and for 120 dB (the recommended level for watching movies with special effects like thunder, explosions, etc.) — already 100 mW.

At the same time, when choosing by this parameter, note that the actual power of the amplifier at the output will depend on the impedance of the headphones. This paragraph usually indicates the highest power value — with the minimum allowable resistance; for "ears" with numerous ohms, the power will be less, sometimes quite significantly. Therefore, when choosing, it is more convenient to use not a total number, but a specific power value for a parti...cular resistance (see below). The second nuance is that for multichannel amplifiers (see "Number of channels") this parameter can be indicated in different ways: in some models, the power is given for the full channel load mode (that is, we are talking about a guaranteed maximum per channel), in others — for half load or generally for working with one channel; such details should be clarified separately.

Rated power delivered by the amplifier when connected to headphones (or other load) with an impedance of 32 ohms.

By itself, the rated power is the highest average power that the device is capable of delivering for a long time without overloading; individual "jumps" of the signal may have a higher level, but in general, the capabilities of the amplifier are determined primarily by this indicator. At the same time, the physical features of the audio equipment are such that the actual power delivered to the load will depend on the resistance of this load. Therefore, in the characteristics of headphone amplifiers, data is often given for different impedance values. A resistance of 32 ohms allows you to achieve quite good sound quality by the standards of low-impedance headphones, while it is not so high as to create problems for the built-in amplifiers of smartphones and other compact equipment. Therefore, most wired general-purpose (non-professional) headphones are made precisely in this resistance, and if the amplifier characteristics generally indicate power for a certain impedance, then most often it is for 32 ohms.

In the most modest modern amplifiers, the output power at this impedance is between 10 and 250 mW ; values of 250 – 500 mW can be called average, 500 – 100 mW are above average, and the most powerful models are capable of delivering ...f="/list/788/pr-19429 /">more than 1000 watts. The choice for specific power indicators depends on the sensitivity of the headphones used, as well as on the sound pressure level (in other words, loudness), which is planned to be achieved by the amplifier. There are special formulas and tables that allow you to calculate the minimum required power for a certain volume at a given sensitivity of the "ears". However, in the case of 32-ohm headphones, it does not always make sense to "get into the calculations." For example, the mentioned 10 mW is more than enough to drive headphones with a modest sensitivity of 96 dB to a volume of more than 105 dB — this is already enough to listen to music at quite a decent volume. And in order to achieve the same "ears" level of 120 dB, which provides a full perception of the loudest sounds (like explosions, thunder, etc.), you need to give out a power slightly higher than 251 mW. So in fact, you have to pay attention to this characteristic and resort to calculations / tables mainly in those cases when you have to use 32 Ohm headphones with a relatively low sensitivity — 95 dB or less.

Rated power delivered by the amplifier when connected to headphones (or other load) with an impedance of 16 ohms.

By itself, the rated power is the highest average power that the device is capable of delivering for a long time without overloading; individual "jumps" of the signal may have a higher level, but in general, the capabilities of the amplifier are determined primarily by this indicator. At the same time, the physical features of the audio equipment are such that the actual power delivered to the load will depend on the resistance of this load. Therefore, in the characteristics of headphone amplifiers, data is often given for different impedance values. And 16 ohms is a rather low resistance indicator even for low-resistance "ears"; such characteristics are provided mainly in general-purpose headphones designed for pocket gadgets with low-power amplifiers.

As for the choice for specific power values, it depends on the sensitivity of the headphones used, as well as on the sound pressure level (in other words, loudness) that is planned to be achieved by the amplifier. There are special formulas and tables that allow you to calculate the minimum required power for a certain volume at a given sensitivity of the "ears". At the same time, it is worth noting that at 16 ohms, even the most low-power modern “amps” are capable of delivering about 20 mW — this is enough to drive headphones with a sensitivity of 88 dB (far from the highest figure) to a vo...lume of 105 dB (the minimum value recommended for a complete listening experience). And in most amplifiers, when operated with a given impedance, they provide much more power. So paying attention to this point and going into the calculations makes sense mainly either with low sensitivity of the "ears" (less than the mentioned 88 dB), or if you want to end up with a level above 105 dB.

The ratio between the overall level of the desired signal produced by the amplifier and the level of background noise resulting from the operation of electronic components.

It is impossible to completely avoid background noise, but it is possible to reduce it to the lowest possible level. The higher the signal-to-noise ratio, the clearer the sound produced by the device, the less noticeable its own interference from the amplifier. In the most modest amplifiers from this point of view, this indicator ranges from 70 to 95 dB — not an outstanding, but quite acceptable value even for Hi-Fi equipment. You can often find higher numbers — 95 – 100 dB, 100 – 110 dB and even more than 110 dB. This characteristic is of particular importance when the amplifier operates as a component of a multi-component audio system (for example, "vinyl player — phono stage — preamplifier — headphone amplifier." The fact is that in such systems the final noise of all components at the output is summed up, and for sound purity it is extremely it is desirable that these noises be minimal

Separately, it is worth emphasizing that a high signal-to-noise ratio in itself does not guarantee high sound quality in general.

The coefficient of harmonic distortion that occurs during the operation of the amplifier.

Any electronic circuits are inevitably subject to such distortions, and the quality and reliability of the sound at the output depends on their level. Accordingly, ideally, the harmonic coefficient should be as low as possible. So, as a general rule, a level of 0.09% and below (hundredths of a percent) is considered good, and a level of less than 0.01% (thousandths of a percent) is excellent. The exception is lamp devices: higher values \u200b\u200bare allowed in them (in tenths of a percent), however, this point in many cases is not a drawback, but a feature (for more details, see "Lamp").

It is also worth noting that a low harmonic coefficient is especially important when using the amplifier as part of multicomponent audio systems — for example, when listening to music from a vinyl player with an external phono stage. The fact is that in such systems the sum of distortions from all components affects the final sound — and it, again, should be as low as possible.

The presence of the Gain Control function in the amplifier — that is, adjusting the input sensitivity, or, in other words, adjusting the degree of gain. The higher the "gain" — the higher the final volume of the sound (with the same characteristics of the headphones and the input signal).

Most often, modern headphone amplifiers provide the simplest two-stage (High / Low) or three-stage (High / Mid / Low) sensitivity adjustment. However, even such a setting provides additional features for coordinating the signal source, amplifier and headphones. For example, the ability to increase Gain may come in handy when changing headphones to higher-impedance or less sensitive ones: a weak gain sometimes does not allow you to achieve the desired volume on such “ears”. Conversely, for sensitive headphones, a high degree of gain may be excessive.

The way to adjust the level provided in the amplifier, in other words, the way to control the volume.

Most often, a special wheel(rotary control) is responsible for such adjustment, however, there are also models with buttons. Here are the features of each option:

— Wheel. The most common type of volume control nowadays; its popularity is due primarily to two things. The first is ease of use: the control of the wheel is intuitive, and besides, such a knob can be found and turned by touch, blindly, without much difficulty (this is especially important for portable models — see "Type"). The second point is versatility: the wheel can be connected both with the simplest analogue control loop and with a digital circuit. Moreover, analogue control (considered optimal for high-end equipment) in modern headphone amplifiers is carried out only by rotary controls. The disadvantages of this option include perhaps some bulkiness compared to buttons, but even in pocket models this moment is often not critical.

— Buttons. Volume control with buttons; it can be either two separate keys or a rocker like those used in many portable gadgets. Anyway, such controls are more compact than castors. On the other hand, such control is carried out only electronically: the buttons send a signal to the control circuits, which change the volume accordingly. This format is considered less suitable for h...igh-quality audio equipment than analogue control: additional digital circuits not only complicate the design, but are also a potential source of additional noise. Therefore, push-button control can rarely be found nowadays — in certain models of portable amplifiers (see "Type"), where this solution is provided mainly to reduce the size.

Operating time of the battery-powered amplifier (see "Type of power") on one battery charge.

Note that this indicator is rather conditional, since the characteristics most often indicate a certain average operating time: at relatively low power, with minimal use of additional functions, etc. So in fact, the battery life may differ from the claimed one by one , and the other side — depending on the features of the application. Nevertheless, in general, this parameter well illustrates the real capabilities of the device, according to the claimed operating time, it is quite possible to evaluate the overall battery life of the amplifier and compare it with other models: the differences in the claimed figures will most likely correspond to the differences in the real battery life (ceteris paribus ).