(under subclass 70) Subject matter wherein power supply current for one or more vacuum tube amplifying devices is supplied through at least two separate space discharge paths of at least two vacuum tubes.
(1) Note. Subject matter including separate and distinct groups of pairs of vacuum tubes having separate and distinct series energized space discharge paths is also included in this subclass.
(2) Note. A series of three or more vacuum tubes arranged in series for power supply which comprises a single discharge path for the anode power supply is excluded from this subclass.