How to eliminate the buzzing sound after a while?

There is a bit of a problem with the input cable connector connecting the speaker and the device, and it is not tightly connected. Solution: Unplug the cable and reconnect it. Power filtering.

Defects are caused by the fact that there is always a humming "communication sound" in the loudspeaker, regardless of whether there is a signal or not. As a solution, you can add a power filter to the power supply of the input amplifier.

With my many years of experience in the research and development of power amplifiers, I will share a diagnostic method with you, the power amplifier is powered on and no load, and when there is a buzzing sound, open the power amplifier cover, and touch whether the transformer is heating and vibrating, which is the "magnetostriction" problem of the transformer, which will cause the electrical noise of the transformer to be transmitted to the power amplifier board and finally make the woofer hum, and the older the transformer, the more obvious the phenomenon. In the case of a subwoofer, the hum is a superposition of the power supply voltage noise and the physical vibration of the transformer, and the phenomenon is more pronounced. The first way is to increase the power filter capacitor to alleviate the symptoms, and the second way is to replace the high-quality ring cattle.

This situation of the power amplifier is very likely to be due to the shielding of the pre-input circuit of the power amplifier, resulting in the audio socket input components can not be shielded, and the AC signals sensed by the components and lines are amplified step by step, so this [humming] sound is formed.

Troubleshooting can be done by carefully identifying the fault site at the pre-amp input.

Many times when using the power amplifier, there will be an inexplicable "hum" current sound, in this case, you can take the following methods to try.

Judgment and elimination of humming fault of power amplifier: 1. AC sound. Turn on the speaker, and turn off the volume potentiometer to the end to the silent state, at this time the speaker continues to hum, first check whether the four rectifier diodes in the power supply circuit are intact, if they are intact, it means that the power amplifier circuit in the power filter capacitor leakage, the capacity is too small, desoldering, should replace the same type of capacitor, or increase the filter capacity.

As shown in the figure (rectifier diode and filter capacitor circled in red): 2. As the volume increases, the hum also increases, which means that the noise is in the pre-amp, first of all, unplug the audio source input wire, and then turn the volume up, if not, it is a problem with the audio input shielding wire, repair or replacement. 3. After unplugging the audio cable, there is a buzzing sound, which means that the voltage amplification circuit of the pre-amplifier is faulty and needs to be repaired by the master.

The power transformer will produce AC sound if the magnetic flux leakage is smaller, the power filter capacitor capacity will be smaller, the power amplifier quiescent current will be seriously large and will produce AC sound, the signal line will be shielded poorly AC sound, the grounding terminal will not be in accordance with the principle of one point grounding will produce AC sound, and external interference will also produce AC sound when it enters the power supply. There are many reasons for this.

The sound of electrical current emitted by the distortion of the amplifier.

1.Check whether the signal input ground is good?

2.Is the sound too loud? Most of the amplifiers on the market are Class B amplifiers, and the volume will be distorted when the volume is adjusted above 50%.

3.The power amplifier works for a long time under the condition of poor heat dissipation, which leads to the super stability of the power amplifier tube, and it will also be distorted.

There are many reasons for this, such as abnormal performance of filter capacitors, poor grounding of circuit boards, aging of audio lines, etc.

The power amplifier has a humming current sound and the solution is as follows:

1. Electromagnetic interference.

Electromagnetic interference can be mainly divided into power transformer interference and stray electromagnetic wave interference. Power transformer interference: due to the power leakage of the multi-speaker caused by magnetic flux, the effect of installing a shielding cover for the transformer is very obvious when conditions permit, and the magnetic flux leakage can be blocked to the greatest extent, and the shielding cover can only be made of iron materials.

We should try to choose products with big brands and solid materials, and in addition, using external transformers 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. Do a good job of connecting the connecting line and connect the interface.

Specific methods: broadcast wire, wiring should be good, there can be no broken wire and the line and the power amplifier shell has contact, do not tie the wire together with a trapped wire, to use a good quality wire, tighten the wiring place, the power cord is best connected to the live wire and the zero line 2, each interface must be connected, so there will be no noise.

3. Analyze the problem of failure and prescribe the right medicine.

Specific method: First, determine whether there is a communication sound when the audio input is not connected or the input plug is not plugged in, and if so, it is an internal problem. The problem in the machine is to check whether the filter circuit is effective, and it can be tested by measuring the capacitance of the filter capacitor or by connecting the same capacitance in parallel.

Replacing a good capacitor can solve this problem. Caused by unreasonable wiring: Check whether the input wire and ground wire wiring are reasonable.

Check that the shield of the transformer is grounded, otherwise there will also be an AC sound. 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.

4. Treatment methods under poor contact.

The current sound of the power amplifier may be due to the poor contact between the input circuit of the power amplifier and the previous circuit to the "ground", such as the loose ground end of the volume potentiometer, the poor grounding of the shell, the common end of the signal line between the pre-amp and the post-amp or poor contact, etc. Of course, the excessive quiescent current of the final power amplifier tube of the ordinary power amplifier circuit will also cause current sound.

There is a buzzing sound after the amplifier is turned on, what is the reason.

1. If there is a problem with the sound card of the computer, replace it with a new driver. 2. There is no large power electrical appliances around the speaker, and there is electromagnetic radiation. 3. Problems with the speaker itself, such as the power supply circuit in the speaker, audio circuit, power amplifier circuit, etc., try it in another place, if there is still a buzzing sound, find a professional maintenance master to repair it.

4. If there is poor contact between the audio line connected to the computer, you can wipe it with alcohol, and then reconnect it with silver. 5. After connecting the speaker, turn off the volume lower, if"Buzz"The sound is gone, the current of the power supply is small, you can increase the power filter capacitor to try.