A DC connector (or DC plug, for one common type of connector) is an electrical connector for supplying direct current (DC) power. Compare to domestic AC power plugs and sockets, DC connectors have many more standard types that are not interchangeable. The dimensions and arrangement of DC connectors can be chosen to prevent the accidental interconnection of incompatible sources and loads. Types vary from small coaxial connectors used to power portable electronic devices from AC adapters to connectors used for automotive accessories and for battery packs in portable equipment.
If you are simply plugging your instrument to listen to music, you would not necessarily need an audio jack with switches. However, if you are needing to switch the audio between speakers and headphones, detect when the plug is inserted, use the inserted plug to control other portions of your circuit, or are using an audio mixing board, you will likely want to use a connector with a switching function.