Helical scan tape recorder without head-tape contact in stand-by mode

The support for a magnetic head rotating about an axis is relatively movable with respect to a circular cylindrical guide surface which guides the tape past the path of the rotating magnetic head. In the playing mode, the rotation axis is coaxial with the cylindrical guide surface axis. In a stand-by mode either the bearing support for the rotating head assembly, or the cylindrical guide surface, is moved radially a small distance away from the other such that the head remains in contact with the guide surface, but is clear of the path swept by the rotating magnetic head. When the two portions of the device are moved back into coaxial alignment for the playing mode, a position device locates them accurately so that the two axes coincide.