Well,
The Fairchild is one of the quietest units I have ever used, the audio is just going trough a very simple classA 6386 (ok, 8 of them) amplifier, remember, it was designed as a no-compromise mastering limiter at a time when the record industry was pushing for 'hifi-quality' (the mid 60's). The input and output transormers are ENORMOUS, so is its headroom. The unit is almost transparent when no gain reduction is applied, but as soon as you start limiting...well, magic sets in...your mix becomes punchier and yet somewhat more open...
You can also use it as a tracking compressor on just about anything, it does wonders on a lead vocal, or saxophone or bass...
Some pieces of equipment are more than just machines: a good U47, a Pultec EQ1A, an ATR100 1/2, a Memory Moog, ATC20A, VOX AC30, a beige 1961 Fender Bassman...
B.