FET output parameters are somewhat similar to tubes and have also more limited impedance stability than bipolar transistors. The most negative factor of FETs is small gain that is even less than tube. That dictates a demand of multiple previous driving stages 2 or three before the actual output.
Bipolar transistors despite having less linear output characteristics are more stable to different impedance loads and have sufficient gain to be used with only one input stage(in-theory).
Bipolar transistors despite having less linear output characteristics are more stable to different impedance loads and have sufficient gain to be used with only one input stage(in-theory).