B, no noise tracking method: input power amplifier (RCA), released the CD signal output, check whether there is noise.
没有噪音的跟踪方法：将功放的输入(rca)恢复，解除CD机的讯号输出，检查是否有噪音。
2
In an amplifier, a DVD, or a CD player, the sound signal consists of electrons, which are processed and moved quickly and precisely between the components with almost no loss of important information.