Toroidal transformer
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.
Power per channel (8Ω)
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.
RCA
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.
XLR (balanced)
The number of
stereo inputs in the design of the amplifier with XLR connectors having three pins and capable of providing the so-called balanced connection. Note that we are talking about an analogue line input, the signal from which passes through all additional processing circuits (for example, bass / treble settings, see "Adjustments"); do not confuse it with Main and balanced digital AES / EBU — these are different interfaces, despite the identity of the connectors.
The main advantage of this connection is that the functions of noise reduction and shielding from interference are performed by the cable itself. This moment is especially useful when it is necessary to connect system components located at a large distance from each other (from 2 m): a balanced cable maintains signal purity even at a rather large length. The quality of such a connection is at least indicated by the fact that balanced XLR is a standard interface for professional recording studios. And its presence in the amplifier, usually, indicates a high level of the device.
There are usually two XLR inputs in amplifiers — this is the minimum number needed to work with stereo sound, and more is most often not required in fact.
Trigger output
The number of
trigger outputs in the amplifier design. Trigger outputs are used as part of the external device control system (see "Advanced"), namely for power management: when turned on, the amplifier supplies a control signal that "wakes up" other components of the audio system (for example, a receiver or subwoofer); this way you don't have to include them separately. Of course, these components must be equipped with trigger inputs to use this feature.
Chassis material
The material from which the base of the amplifier is made is the internal frame on which boards, a transformer and other circuit components are mounted. Theoretically, this moment can affect the sound quality, because. different materials have different magnetic properties, differ in the degree of shielding of the hardware from interference, etc. However, in modern factory-assembled amplifiers, the sound characteristics depend on a huge number of other factors, much more significant, and against their background the influence of chassis materials is completely lost. Therefore, in fact, only the weight and cost of the device depend on this parameter, and even then only slightly.
The following variants can be used in modern devices:
— Aluminium. This material combines good strength and low weight, durable, but quite expensive.
— Steel. Steel is very reliable, while being easy to process and inexpensive. Its main disadvantage can be called a lot of weight.
— Copper. Due to a number of physical properties, copper is considered a well-suited material for high-end electronics. On the other hand, it is quite heavy and expensive to manufacture.
— Dural. An alloy based on aluminium and copper, which is a cross between these two materials: it weighs significantly less and costs less than copper, while at the same time, the characteristics of duralumin are considered more advanced than those of pure aluminium.
