(under subclass 118) Subject matter wherein the two amplifying devices in push-pull are vacuum tube amplifying devices and wherein the input electrodes or the output electrodes are the cathode electrodes of the vacuum tube amplifying devices.
SEE OR SEARCH THIS CLASS, SUBCLASS:
158+, for amplifiers with interstage coupling to the cathode of an amplifying device.
168, and 172, for interstage coupling from the cathode.
186+, for input coupling to the cathode. See the search notes thereunder.
193+, for output coupling from the cathode. See search notes thereunder.
