A new stereophonic amplifier

A central feature of the new design of a stereo amplifier is an output transformer with original features that makes possible reduced cost and improved performance at the same time. This paper discusses a varied possibility of design objectives for a stereo system, and explains the way in which the new output transformer functions. By variation in its method of use, or in choice of parameters, a whole range of amplifiers can apply advantages in different proportions or degrees. The basic design of an output transformer, which is essentially inexpensive to make, provides for separation between "left" and "right" as well as crossover, and combining networks for mixed lows, if desired, without additional external circuits. It makes possible a new type of tone control, achieving high performance economically, using feedback, and/or improved matching between amplifier and loudspeakers over the entire frequency range as well as better separation and efficiency than the single-ended and push-pull transformer matrix can give. One particular amplifier is discussed in detail, while a more general discussion shows possible application to more diverse design objectives.