1. Finger size, suitable for small space embedded, output more than 30W need to add heat sink.
2. Boot popular sound.
3. Amplifier work no current sound. Try to enter the wire is not clear. If there is a noise / current sound signal input,
the noise signal will be amplified.
4. CS control shutdown current is only 0.4mA. Power-on quiescent current 28mA.
5. High gain amplification (36DB). Very suitable for weak signal amplification, eliminating the need to increase pre-amplifier, reduce costs. Computer audio input amplifier must be changed to 20DB gain use.
6. With output short circuit protection. Troubleshooting immediately resume normal work.
7. A variety of product pins and size is fully compatible
Benefits of using 36dB of power amplifier gain:
Because the sound source signal of some audio equipment is too weak, the amplified sound with 36dB power amplifier will be very loud, and the amplified sound with 20dB power amplifier on the market will be very small. For example, the output audio signal of a mobile phone is weaker than the audio signal of a computer. Amplifying the sound with a 36dB amplifier is very large. If you use a computer audio signal, use a 36dD amplifier to amplify the sound too much, and the sound is distorted. You should lower the volume of the computer. If the computer is not easy to adjust, you can reduce the volume by inputting a series resistor on the amplifier board (the input resistance of the amplifier board is 1K Use the resistor divider to change the volume of the amplifier, so that the amplifier does not appear amplification saturation distortion), is that the amplified sound is not distorted, and it is not ugly.
The disadvantage of using 36dB power amplifier gain:
If the audio equipment has a faint noise signal when it is muted (no playback), the noise will be greatly amplified by the 36dB amplifier, so some customers say why the amplifier is not loud and has a lot of noise (because the noise comes from the input signal source) There is no noise when the input audio cable of the power amplifier board is disconnected in the speaker). Noise from desktop computers is much louder than laptops. It is generally recommended that customers test using a laptop computer to provide audio sources.
Power amplifier gain description:
The computer audio signal is very strong. The gain of the universal power amplifier is 20DB. Each amplifier must be set to the minimum gain by the buyer. For weak audio signal input, only 36DB gain is used, which saves the cost of the preamplifier circuit.
The gain of the power amplifier is also called the input sensitivity. Set the gain to match the signal output of the host. Its function is to maximize the power output of the power amplifier when the output volume of the host is maximum. Do not use gain as a volume control. If the gain is set improperly, it will often cause clipping distortion of the amplifier or enter a protection state when the setting is too large. If the setting is too small, the power amplifier often does not perform at its best. The key to setting the gain is to ensure that the maximum value of the host is not the true voltage or volume. The experienced technician can judge by listening.
Precautions:
1. After the power amplifier board is powered, the DC voltage between the two pads connected to the speaker is 0V, and the DC voltage between the speaker pad and GND is half of the power supply voltage.
2. Select 4 ohm speakers, the maximum power supply voltage cannot exceed 21V, otherwise the chip will overheat and easily damage the amplifier. Select 8 ohm speakers, the maximum power supply voltage can not exceed 24V, otherwise the voltage is too high to breakdown the power amplifier chip.
3. After the power amplifier board is powered on, hands cannot touch the component pins on the board, because human interference signals interfere with the timing of the digital power amplifier, resulting in damage to the chip and the human body with static electricity-strong voltage will cause breakdown and damage to the chip and human body. Be sure to know.
4, the power supply voltage should be stable, try to use switching power supply and battery power. The power supply must not exceed the working voltage of the board, otherwise the chip will be burned out, and the digital power amplifier will be very coquettish, which is not the same as the analog power amplifier, and the working method is completely different.
5. As far as possible, the speaker wiring should be controlled within 3 meters with an audio cable. If the line is too long, the inductance of the load increases and the self-inductive voltage is too high to break down the power amplifier chip. It is recommended to consider adding a diode (IN5819) to realize the self-inductive voltage when the long-line is connected to the speaker Release protection chip.
6, 12V power supply basically does not need to add a heat sink, if the chip temperature is higher than 60 degrees, because immediately stop working, add a heat sink fan heat, otherwise the temperature will burn the chip immediately, the output of high power 50W is recommended to use 5CM long * 1.4CM Wide * 2.5CM high volume heat sink.
Tips:
1. The power amplifier board defaults to 36DB gain. The computer input can only be turned on at a maximum of 20% volume, otherwise it will be seriously distorted due to amplification, the power amplifier chip will be seriously heated and damaged, and the speaker will be damaged at the same time. The phone input can turn on 90% of the volume, because the phone audio signal is much weaker than the computer. To turn on the computer at 90% volume, you must reduce the gain of the power amplifier board and short the two 20DB gain pads on the board. Once the input audio signal is too strong, the amplifier's amplification gain must be reduced, otherwise the amplifier will have amplification distortion and severe distortion amplification-exceeding the output power of the amplifier will damage the chip.
2. It is not recommended to use the default 36DB gain. The amplification capability is too strong, and weak signals are easily amplified. Once the input signal is too strong, the power amplifier is easily distorted and seriously distorted and amplified-exceeding the chip's own output power will damage the chip.
Common sense of electronic power supply:
24V voltage cannot be directly supplied to the power amplifier board because 24V is directly supplied to the power amplifier board. The voltage is too high, the capacitor is short-circuited for a short time, and the current will be super large. In addition, the 36DB gain of the power amplifier will cause a sudden sudden change in the capacitor's strong current. The amplifier is large, and the power amplifier chip exceeds its own output power and is damaged by short circuit. The 24V voltage can only be turned on and off by switching on the power supply and starting the 220V voltage to buffer the 24V voltage, thereby restraining the problem of instantaneous high current. (24V battery or lithium battery power supply, can only connect 1-2ohm 5W resistor in series with VCC pin to limit the current, thereby reducing the problem of excessive instantaneous current.)
