(under the class definition) Subject matter including at least two sources of signal voltage which are combined in the amplifier so that the signal output of the amplifier is a linear function of the sum or difference of the signal input sources.
(1) Note. Balanced input circuits or balanced output circuits are considered single signal sources or loads in this class. Therefore a balanced to unbalanced amplifier is not classified in this subclass but in subclass 116 below.
SEE OR SEARCH THIS CLASS, SUBCLASS:
74, for series energized vacuum tube amplifiers with plural separate signal inputs.
81, for signal feedback amplifiers having at least one push-pull stage.
116, for amplifiers having balanced-to-unbalanced coupling. See (1) Note above. 118+, for amplifiers including a push-pull stage.
124+, for amplifiers with plural amplifier channels.
147, for amplifiers having plural signal inputs. See the notes and search notes thereunder.
252+, and 295, for semiconductor amplifiers having plural channels or plural inputs.
301, for semiconductor amplifiers having balanced-to-unbalanced or unbalanced-to-balanced coupling.
