I believe the 'DMC' was intended to be DAC and Amp(lifier). When reproducing audio there are a couple of 'steps' that need to occur depending on the type of media used for recording the music. Here are some examples:
1) Digital audio, read from a disc or drive is stored as 1's and 0's (oversimplified). This means it is not an analog waveform, aka not something we can directly make louder and then hear. To get from those 1's and 0's to hearing sound something needs to read the file and turn it into an analog output. This is the purpose of a Digital to Analog Converter or DAC. Once you have the file converted to an analog form it needs to be sent to the device that will physically move to reproduce the sound (speakers or headphone). Different devices have different power needs to be able to take the converted signal and turn it into sound. This is the role of the amplifier in the signal chain. It takes the analog signal from the DAC and cuts or boost the 'strength' of that signal before passing it along to the speakers or headphones.
2) Analog audio, like tape or vinyl records, is stored in a manner that is directly analogous to the recorded sound produced during the performance. This does not require conversion before amplification, only something to read the media (magnetic tape head or record stylus) which generates an output voltage. This too then requires an amplification stage or multiple stages to cut or boost the strength of that signal on its way to the speakers or headphones.
Hope that helps, feel free to ask clarifying questions.