The achievement of adequate signal-to-noise ratios in the measurement of the energy released by ionizing particles in detectors of large capacitance such as, for instance, calorimeter cells, frequently relies upon transformer coupling between detector and preamplifier. Such a solution, however, may not be feasible if the detector is located in a strong magnetic field. This paper discusses the possibilities opened up by a recently developed field effect transistor of large gate area, whose design has been tailored to the applications in front-end preamplifiers for calorimeters and other large capacitance detectors of frequent use in elementary particle physics.