Fertah

Sounds fantastic and in class with other high-end SSL inspired compressors. As I understand, the circuit design is very close to the original, with additional features such as dry/wet mix and the sidechain circuit inspired by API 2500. It can sound really transparent and unnoticeable on most settings, almost without any coloration. Although with really fast attacks and releases, and a higher ratio it can be pretty squishy and coloring, in a good way. When the input transformer is engaged, I hear the difference in the transient response and harmonic distortion in the higher register. Without it engaged, it is a bit cleaner and 'more modern' sounding, whereas with it engaged, it has a slightly more old-fashioned feel. The output transformer seems to add some harmonics to the low end. It really depends on the program, but it can either add a nice warm low end or make things a bit muddy. Both can be very useful in certain scenarios.