First, the difference in the form of output:
1. The constant pressure is not a certain voltage, but the output form is constant pressure, which requires the rated voltage of the load to be constant. The constant voltage amplifier is connected in parallel with a plurality of constant voltage speakers as long as the total power does not exceed the total power of the constant voltage amplifier.
2. The fixed resistance power amplifier requires a certain output load resistance. In a fixed-resistance amplifier, if the load impedance changes, the power changes. The 8 ohm 100W fixed-resistance amplifier becomes 4 ohms and becomes close to 200W.
Second, the characteristics of constant pressure amplifier:
In a constant voltage amplifier, if the rated load voltage changes, the power changes accordingly. The 100V, 10W speaker is connected to the 5V at 5V (the power difference between 100V and 70V is doubled). The domestic constant pressure standard is 120V, 240V. The foreign constant pressure standard is 70V, 100V.
Third, the characteristics of fixed resistance amplifier:
Power amplifiers with fixed resistance outputs: These amplifiers require a constant impedance of the load. When the input signal is constant, the output voltage varies greatly with load.
Power amplifier with constant voltage output: Since the deep negative feedback device is used in the amplifier, the deep negative feedback is generally above 10~20dB. Therefore, the output impedance of the amplifier is low and the load changes within a certain range. The output voltage can still maintain a certain value, and the sound quality can remain unchanged.
Fourth, the difference between constant pressure power amplifier and fixed resistance power amplifier application:
Constant pressure is used to require a large space where the sound quality is not very high. On the contrary, the fixed resistance can only be transmitted within 100 meters due to the limitation of transmission. Therefore, it is generally used in a small space when the sound effect is relatively good. The general broadcast system uses a constant voltage output, and the sound system uses a fixed resistance output.
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