How to solve the sound current of the sound amplifier? (I)

How to solve this current sound?

Everyone has different definitions of "current sound". First, find out which kind of "current sound" you encounter. Most people think that the current sound is caused by poor grounding, so they try to ground the outer casing of the amplifier and even shield the whole amplifier with a metal cover, but the current is still sound and there is no countermeasure.

In more than half of the cases, there is no problem with grounding. "Current sound" is not caused by static electricity. But looking at the descriptions of different friends, "current sounds" are:

Continuous noise

The loudness of the noise is quite stable

Usually low frequency noise

In the experience of all the friends, the "current sound" can be summarized in the following cases:

Power Ripplenoise, ie Humming

Pick-upnoise includes body pickup noise (Bodypick-up)

Layout or Groundingtopology

Bad ground noise (Groundnoise) and circulating ground (Groundloop)

Bad wiring and shielding strategy (Badwiringandshieldingstrategy)

Communication buzz:

The cause of the AC hum is the improper design of the power filter, or even cut corners, causing some of the AC signal from the mains to slip into the amplifier. This type of current sound is characterized by a very low frequency, which is very weak in most cases. It is only heard when the ear is placed against the speaker, and even if the volume is set to a minimum, the noise still exists.