[en] The first stage of the charge sensitive preamplifier of the high energy resolution Si(Li) X-ray spectrometers is a cooled junction field-effect transistor (FET) exhibiting low level of noise. The spectrometer manufacturers use selected FET chips mounted into low dielectric loss material. Noise measurements have been performed for selection of low cost commercial FETs of type 2N4416 from different series of Texas Instruments factories. The FETs were encapsulated and mounted into a teflon block. The measurements have been carried out in a high impedance gate mode in time domain. The noise measurement arrangement, the results of selection of FETs and some observations on generation-recombination (GR) noise of FETs are described. (author) 9 refs.; 8 figs