Number of channels
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.
For acoustics
The number of outputs in the design of the amplifier, designed for direct connection of speakers. One such output is usually a pair of screw terminals designed to connect one speaker. Accordingly, the standard set for sound in stereo mode is two outputs (two pairs). However, in multi-channel devices (see “Number of channels”), as well as in models with the ability to connect additional speakers and/or Bi-Wiring (see “Additionally”), more speaker outputs are installed — in accordance with the capabilities of the amplifier.
Power consumption
The power consumed by the amplifier during normal operation. Some manufacturers may indicate average power values, some — indicators at maximum load. However, anyway, this parameter allows you to quite adequately assess the power consumption of the device and the requirements for connected power.
In addition, it can be useful if you have doubts about the accuracy of the claimed data on the output power (see "Power per channel (8Ω)"). The basic rule is that the total power rating of all channels cannot exceed the total power consumption of the amplifier. In addition, there are special formulas that allow you to derive the maximum possible rated power depending on the power supply and type of amplifier; they can be found in special sources.
