Several of the components used to implement a wireless transmitter, such as a DC-powered FM transmitter usable for playing media content from a personal media player over a vehicle's FM radio, are organized using an arrangement by which a controller that includes a user interface is removably couplable to a charger plug that interfaces with a power source. An arrangement for removably coupling a device connector in the transmitter to the charger plug is also provided. In an illustrative example, the controller and charger plug are configured with magnetic elements which are used to retain the controller against an end of the charger plug using magnetic force. A portion of the device connector is removably insertable into an elastically deformable connector cap that is configured to removably slide over the charger plug end.