All audio systems are made up of these parts.
1. Audio source, that is, the part that provides audio digital signal. If it is a computer, it is a hard disk or optical drive. If it is a table player system, it is a CD turntable.
2. Decoder, which outputs digital signal to decoder from sound source, and converts digital signal to analog signal.
3. The power of the amplifier, the analog signal output by the decoder, is not suitable for the direct use of the speaker or earphone, so the amplifier should amplify the signal to become the signal suitable for the use of the speaker and earphone.
4. Finally, the speaker part, speaker or earphone.
This is the composition of a standard audio system. All devices, whether high-end hundreds of millions of fever level devices or hundreds of dollars of Walkman, have these parts. But the Walkman device integrates all parts into a small machine, that is to say, there are decoding circuits and amplification circuits inside. Some high-end devices are mostly separated from each other, and some can be equipped with pre amplifier and post amplifier separately.