A phone connector (also called jack plug, stereoplug) is an electrical plug that is used in audio systems. For example, it is used in electric guitar cables to connect the guitar to an amplifier. There are typically three different sizes of phone connectors: 6.3 mm, 3.5 mm and 2.5 mm diameters.
Balanced and unbalanced circuits are possible with stereoplug connector when using monosignal per one stereoplug. Sound quality improves with a balanced circuit because noise signal reduces, especially with microphones where the signal is often weak.