A mass spectrometer is disclosed comprising an ion optics device housing having one or more external electrical connectors (1719) provided thereon. An ion optics device (301) is arranged inside the ion optics device housing, the ion optics device (301) comprising one or more electrodes for manipulating ions, the one or more electrodes being electrically connected to the one or more external electrical connectors (1719) provided on the ion optics device housing. A voltage supply housing (1717) is provided having one or more external electrical connectors provided thereon. One or more voltage supplies are arranged inside the voltage supply housing (1717), the one or more voltage supplies being in electrical communication with the one or more external electrical connectors provided on the voltage supply housing. The one or more external electrical connectors provided on the voltage supply housing are directly physically and electrically connected to the one or more external electrical connectors (1719) provided on the ion optics device housing.