Pre-amp and pure power amplifier are different!Car stereo Vendor!

source:Industry News release time:2021-10-27 Hits: Popular:Brand bar audio wholesale

　　Pre-amp and pure power amplifier are different

　　1. Concept

　　The front audio power amplifier is generally a differential reduction circuit or a common collector reduction circuit. The second is to select a differential mode signal that needs to be reduced from the signal, and the front of it is usually connected to a multi-stage common emission reduction circuit for small signal reduction. Most of the front-end boost is the signal voltage rather than the current. The function of the front-end is to initially reduce the signal and complete the volume adjustment.

XD18C Big sound bar Merchant

　　The output signal of the pure post-stage power amplifier is very complicated, that is, it takes the input of the pre-stage and adds the power of the signal. The later stage is connected to a high-impedance rear stage, which mainly provides a suitable input voltage. The rear-stage reducer is connected to a low-impedance speaker not only to provide a suitable voltage, but also to provide sufficient current.

　　2. Features

　　Pre-amplifier refers to the circuit or electronic equipment placed between the signal source and the reducer stage, and is designed to withstand the weak voltage signal from the signal source.

　　The preamplifier is used to reduce the weak signal. Generally, the signal is first passed through the electrolytic capacitor to filter out the high-frequency music signal, and then enter the negative reaction operational amplifier to reduce the signal. Pre-amplifier generally refers to reducing the power of AC signals, that is, reducing the current and voltage of electrical appliances without distortion of the signal. The front is placed close to the detector, the transmission line is short, the scattering capacitance Cs is reduced, and the signal-to-noise ratio is improved. The signal is initially reduced by the preamplifier, which increases the absolute influence of external disturbance. The preamplifier is designed with high output impedance and low input impedance to complete impedance conversion and matching.

　　If you talk about the technology alone, the preamplifier requires more precision than the pure post-amplifier, and it is more difficult to make it. If you want to add a special power cord, it is relatively impossible to use a good line in the post-stage due to the large current of the post-stage. It should be the previous level.

　　The output signal of the pure post-stage power amplifier is very simple, which is to accept the input of the pre-stage. But the load of the pure power amplifier is the speaker, which is what makes many audio fans and even magazine review writers unsure. The rear stage is the load of the front stage, which is a high-impedance load; the speaker is the load of the rear stage, which is a low-impedance load. It looks the same, only one word short, but the high and the low impedance creates a scene that it is easy to push or unable to push. The later stage is connected with a high-impedance rear stage, which mainly provides an appropriate input voltage, due to the rear-stage expansion machine.

　　Three, the scope of use

　　The pre-reducer is usually connected to a pure power amplifier, the front input is connected to the output of the latter, and the latter is connected to the speaker. The pre-reducer is to reduce the voltage, the pure post-stage power amplifier is to reduce the current, and the pre-reducer is the link device between various audio equipment and the power reducer. The input signal level of the audio equipment is relatively low and cannot promote the power reduction. The normal task of the pre-reducer, and the pre-reducer plays the role of signal reduction. It is mostly suitable for public places such as communities, commerce, and offices.

　　Pure post-amplifiers require pre-scalers to advance. The power of pure post-amplifiers is usually over a few hundred watts. It is usually used in some professional places, and multiple speakers are simultaneously tasked to drive different speakers. Therefore, there is no low-level output port and no socket for high-impedance output signals such as microphones. This requires adding a pre-reducer or a mixer to the signal to control it. The pre-reducer and pure power amplifier are also combined into one, usually the power is not less than 300 watts, and is used in relatively small places, such as home use or KTV.