Why is there a current sound when the amplifier is turned on for a while, and what is the reason?

1.There is a current sound when the machine is turned on, which belongs to the power board filtering problem, and there will be a circuit component problem after a while.

2.Particularly close to the heat sink.

Nearby components, due to the gradual increase in temperature, the parameter value changes and causes noise.

If the power amplifier is turned on for a while, there is an AC sound, it is likely that there is a problem with the filter capacitance of the rectifier filter circuit of the power amplifier: virtual welding, or the capacity becomes smaller, resulting in the DC ripple coefficient at the output end becoming larger, and the [humming] sound appears after the amplifier is amplified.

This fault focuses on checking the rectifier circuit to see if there is a problem with the filter capacitor. In addition, you should also check that the shield wire of the audio input interface is good, if the shield wire is disconnected, it will also cause an inductive communication sound.

The current sound is caused by the interference of the power shield or the peripheral interference (specific external environment), generally the socket 220V, the interference of the grounding wire of the seat or the ground wire is not good (disconnect the ground wire). It can also be caused by abnormal voltage regulation and filtering of the power amplifier, shielding or magnetic interference between the output of the detection and maintenance circuit and the transformer. . .

Some components are caused by poor thermal stability, such as rectifier diodes, filter capacitors, etc. A small filter capacitor that supplies power to the preamp is also possible. There is also a power amplifier amplifier, because of poor thermal stability, which will lead to serious imbalance in the midpoint, and will also produce AC sound.

There are many reasons why the amplifier has a current sound --- after being turned on for a while, but it is necessary to distinguish carefully.

For example, this communication sound is getting louder and louder with the boot time? Or did it come out of nowhere?

If it is getting bigger and bigger with the boot time for a long time, it is usually the filter capacitor is not good.

If it appears suddenly, it should be a problem such as poor contact and virtual soldering, and it should also appear in the filter circuit.

1.Determine whether it is electromagnetic interference.

Electromagnetic interference is mainly divided into power transformer interference and stray electromagnetic waves.

Interference. Power transformer interference: due to the power supply magnetic flux leakage, the effect of installing a shield cover for the transformer is very obvious when conditions permit, which can block the magnetic leakage to the greatest extent, and the shield cover is best made of iron material (the shield must be grounded).

In addition, using an external transformer is also a good solution.

Spurious electromagnetic interference: It is common for speaker wires, crossovers, wireless devices or computer hosts to become sources of interference. Keep the main speaker as far away from the computer as possible and reduce the number of peripheral wireless devices.

2.Whether the various wiring are in good contact. There can be no broken wire or the wire is in contact with the power amplifier shell, do not tie the wire together with a trapped wire, use the best wire, and tighten (or weld firmly) the wiring place.

3.If there is a communication sound when the audio input is not connected or the input plug is not plugged in, it is usually a problem in the machine. Problems in the machine are first checked for the filter circuit.

Whether it is effective or not can be measured by measuring the filter capacitance.

capacity or in parallel.

The same capacitance method to test. Replacing a good capacitor can solve this problem.

4.Another point is that the shielding layer of the shielding wire from the audio input socket to the power amplifier input should be grounded at one end, and do not use its shielding layer as the low end of the signal to transmit the audio signal, otherwise it is easy to produce AC sound.

5.The current sound of the amplifier may be due to the poor contact between the input circuit of the amplifier and the previous circuit. For example, volume potentiometers.

Loose grounding terminal, poor grounding of the housing, broken common end or poor contact of the signal line between the pre-stage and the post-stage, etc. Of course, the excessive quiescent current of the final power amplifier tube of the ordinary power amplifier circuit will also cause current sound.

First of all, figure out the speakers.

If there is a "hum" sound, it is caused by the change of the capacity of the electrolytic capacitor in the filter circuit of the power amplifier, or the capacity is too small; If the sound is loud and there is a loud "buzzing" sound, it is caused by the poor shielding of the audio input of the power amplifier.

2. The shell of each element must be grounded, and the audio input line must be shielded.

3. The horn has a "hissing" sound, and most of the cases encountered in this case are caused by poor overall shielding, or the primary stage of the power transformer winding is not well isolated. If it doesn't work, connect two 4700p capacitors with a working voltage of 250V in series at the power input end (the power input end of the transformer), and the center tap is grounded, which can also reduce the noise.

The cause of the sound of electric current is generally electromagnetic interference.

Mechanical noise, heat dryness, etc. Otherwise, the card is not properly inserted, the active speaker input is terminated on the speaker output of the sound card, or the sound card driver.

problems. It can be said that it is possible to cause such a situation, both software and hardware.

1. Mechanical noise is unique to active speakers. During the operation of the power transformer, the core vibration caused by the alternating magnetic field will produce mechanical noise, which is very similar to the fluorescent lamp ballast.

The buzzing sound that comes out. Choosing the best product is still the best way to prevent this noise. In addition, we can add a rubber shock absorber between the transformer and the fixing plate.

2. If the potentiometer is used for a long time, the contact between the metal brush and the diaphragm will be poor due to dust accumulation and wear, and noise will be generated when rotating. If the screws of the speaker are not tightened, and the inverter is not handled properly, mechanical noise will also be generated when the **big dynamic**.

This thermal noise can be dealt with by replacing low-noise components or reducing the working load of the components, and reducing the operating temperature is also one of the most effective methods.

3. Electromagnetic interference can be mainly divided into power transformer interference and stray electromagnetic waves.

Interference. The power transformer interference is caused by the magnetic leakage of the power supply of the multi-speaker speaker, and the effect of installing a shielding cover for the transformer is very obvious when conditions permit, which can block the magnetic leakage to the greatest extent, and the shielding cover can only be made of iron materials.

In the case that the power amplifier is not connected to the signal source (only the signal line cannot be connected), the volume is turned on, the sound is basically not heard, and the hand touches the power amplifier without any effect, so the power amplifier is good.

At the same time, this has nothing to do with the so-called polarity of the power input plug.

You see if your amplifier can do it.

Second, you plug in the AC plug at a different pole and listen to whether there is any communication sound.

Poor power filtering - poor signal grounding - power amplifier output deviation from 0V is too large. Sometimes the components are soldered.

Components are components of small machines and instruments, which are often composed of several parts and can be used in similar products; It often refers to certain parts of the electrical, radio, instrument and other industries, such as capacitors, transistors, hairsprings, clockwork, etc. It is mainly divided into: anti-virus components, electronic components, pneumatic components, Hall components, etc.

Components typically come in three forms: button elements.

Movie clips in flash movies have their own timelines and properties. It's interactive, the most versatile and versatile part. You can contain instances of interactive controls, sounds, and other movie clips, or you can place them in the timeline of the button symbol to animate a Crafting button.

Button Symbol: An interactive control button used to create animations that correspond to mouse time (e.g., click, release, etc.). The button has four frames with different states: up, over, down, and hit.

You can create different content on different state frames of the button, which can be a still graphic or a movie clip, and you can give the button an interactive action in the field time, so that the button has an interactive function.

Turn off the volume, if there is any, it may be that the power filter capacitor is open or no capacitance, or it is desoldered. If the volume is turned off and there is no current sound, check the input signal cable.

There are many reasons for current sound, such as poor power filtering, non-standard circuit board design, the quality of the components themselves, the lack of shielding wires and shells, and serious external interference.