When it comes to the amplifier, you must understand the meaning representative of the gain. It is a small signal Level (level) to become a big signal Level, which means that the difference between the small change is called the gain, in principle, we use us. The multiple of the multiple is calculated, but because it is often tens of thousands of times, we use a DB of this marked unit. Usually the amplifier is multiplied in the case of a phase string, the number of DB is added, such as a flat amplifier of a prior stage, when the input signal voltage is 0.1V, and the output voltage is 1V this kind of The 10x amplifier is also a 20DB amplifier. If there is a 10V output of 0.1V, this amplifier is magnified, that is, 40dB amplification.
The table below is the relationship between the magnification and DB and the conversion
Voltage magnification │ 1 │ 2│ 3 │ 4 │ 5 │ 6 │ 7 │ 8 │ 9 │10│10│10│
─────────┼─┼─┼─┼─┼─┼─┼─┼─┼─┼─┤
Voltage gain (dB) │ 0│6 │10│12│14│16│17│18│19│20│18
For example, 60DB voltage gain ratio
60DB = 20dB 20DB 20DB
↓
1000 times = 10 × 10 × 10
For example, 50dB voltage gain ratio
50DB = 20dB 20DB 10DB
↓
300 times = 10 × 10 × 10 × 3
In the sound system, the enlarged gain is generally determined by the input level of the signal source, substantially low-level input and high level input two parts, and most of the low level refers to the singlet input including MM, MIC, After the bonus is increased). High level signals refer to recordings, CD, LD, and generally most audio output signals. The following chart displays the level gain of each amplified level of the sound system.
I want to make and gain related important concepts, 1. Decision gain size is determined by the ratio of the discharge circuitry (feedback), or the ratio of the transformer coil (balance input transformer), and the amplification coefficient of the transistor itself It has nothing to do, so there is no relationship with the volume of the pairing and output of the crystal. 2. The control of gain is generally a controller that is used as a potentiometer as a contemporary gain. In summary, the maneuveration and impedance matching is to determine the real method of gain size.
Finally, I will talk about the relationship between point power sizes and output levels.
Output power speaker load output level output gain input signal voltage
20 W RMS 8 12.66V 29DB 0.45V
50 W RMS 8 20V 29DB 0.71V
100 W RMS 8 28.28V 29DB 1.01V
200 W RMS 8 40 V 29DB 1.42V
The above table We understand the size and gain of the power cannot be mixed, and the small power and high power can only be used by different positions on the volume controller, not the volume size when the volume controller is on the same location on the volume controller. Of course, the various manufacturers have different gains as the basis for good and bad size.
