What the FET?

FET stands for ‘Field Effect Transistor’, which, in the area of dynamics processing, is a type of solid state controllable gain component first employed in a compressor by Bill Putnam, when he redesigned the Urei 176 tube limiter into the legendary 1176 Limiting Amplifier. While the FET was originally conceived as a replacement technology for the valve/tube, the differences between the two are quite profound. First of all, valves and FETs saturate rather differently to each other when pushed hard, FETs being the more transparent of the two at low and high ratios, although they can still get pretty gnarly when pushed. FET-based compressors are also much faster than valves in terms of attack and release times, making them the better option for precise peak limiting. Finally, in the real world, the solid state FET is far more durable and long-lasting than its fragile vacuum tube counterpart – not that that matters in the software domain, of course.