1: Turn on other electrical switches, and the speakers will respond. It shows that your speaker has a high sensitivity. You might as well change its audio line to a shielded audio line, and the cost is about 10 yuan. It is best to cover the power amplifier (front stage) in the machine with a metal cover, and the metal cover is grounded or grounded.
2. Turn on the speaker itself, and there will be a sonic boom. The solution is to use bootstrap switch circuit instead of switch, or turn the speaker to the minimum first.
3: There is a buzz. That's because the capacitor used to remove AC components in the rectifier part of your power supply is broken, or the inductance coil is short-circuited. Generally, the first capacitor in the rectification section is connected in parallel at both ends of the positive and negative electrodes. Just buy another one and replace it according to the above logo (don't connect the positive and negative poles of the capacitor backwards). Another possibility is that the audio line of your signal source is not shielded, which causes electromagnetic waves in space to interfere with the signal source, and the amplifier amplifies this part of the clutter, resulting in buzzing. Just replace the first one with a shielded wire.
If you can't do it yourself, the easiest way is: 1, buy a shielded signal line. 2. Just buy a set of power supply with rectifier and replace it directly. But the cost is higher than repairing it yourself.