Pure rear power amplifier is simply expanding the volume, and the expansion and control of the pre -level. As long as the power amplifier part of the power amplifier. Convenient to all kinds of pre -preparations, and there is a lot of room for promotion. The front of the front and the amplifier is the intact amplifier of the front level and the amplifier level. Generally, the amplifier generally has a pre-stage expansion or tone, volume, etc. with 20 decibels, and there are multiple sets of inputs. Pure rear power amplifier only allows the power to expand, with a maximum volume conditioning, and the input is generally 1-2 groups.

Can you say that, the preceding level, the subsequent force, the front level is the leader and the background. It is not necessary to be able to be able to install a volume potentiometer to control the volume, but the additional level is not only used to control the volume, but it will be worse. It is difficult to say that the impedance is completely matched with the sound source. The amplifier input impedance is often too small, and some sound sources cannot advance the amplifier. At this time, the front stage must be used for impedance matching.

    Other can make the cavity regulating circuit in the front stage, make the front stage of the tuning, participate in the expansion circuit, do the front stage to expand, and so on. The front level is not necessary, but the manufacturer adds the front stage to match various sound sources. The matching of the AV amplifier is one reason. The other is to collect the cavity, input selection, singing and other gathers in the amplifier, and participate in the front level of multiple functions. There are also a small number of uses to satisfy the special needs of some people, such as the pre -level "moisturizing", cavity circuit, electronic frequency division, etc.