Abstract: A plug-in adaptor such as a power pack, transformer or the like in which the inner ends of the plug-in blades, which are connected to the primary, are mounted in molded channels integral with a flange of a coil bobbin, which flange is parallel to the coil length and a cover which encloses the flange and surrounds the blade ends, thus assisting in retaining the ends upon the flange at their connection to the primary and which is clamped to the transformer laminations by fingers extending from the lamination frame; and the bobbin has another extended area providing mounts for eyelets to which secondary leads and other components may be attached.