A turquoise, fluorescent, alphanumeric display is set into the 16mm-thick front panel. In conjunction with three small buttons above it, this display allows the user to choose the input, access the setup menu, and switch the C15 in and out of Idle mode. A button at the bottom left of the front panel brings the amplifier out of Standby mode. At the front of the top panel, a circular, 40mm-diameter button bearing the MBL logo and illuminated with a white ring allows the display to be dimmed in three steps or turned off completely.