Abstract: A portable system of electronic sound equipment for use in vehicles and the like having a direct current electrical system with either a positive or negative ground, wherein the equipment includes one or more of an AM/FM radio, a tape player, and a citizen's band transceiver wired for use with a negative ground, the system including an antenna having a shielded lead and a polarity inverter in the form of a diode bridge circuit and connections with the source of current and the ground therefor and connections to the equipment input and the equipment ground. The antenna lead shield is separated and the portion adjacent to the antenna is grounded to the bridge circuit through a capacitor whereby the connection of the equipment into the direct current electrical system is foolproof with the equipment being operative with such electrical system having either positive or negative ground.