1.2 Product OverviewAbout the Fairchild 670Among gear aficionados, the stereo Fairchild 670 is considered the most coveted of all compressors,not only because of its pristine sound, but also its rarity and price: 670s routinely go for tens ofthousands of dollars on the vintage market. (They originally cost less than $1000.) With 20 vacuumtubes and 11 hand-wired transformers in a hefty 6 rack-space chassis, these hard-to-find units weigh inat a robust 65 lbs.Designed by Estonian-born Rein Narma in the early 1950s, both the stereo 670 and its monocounterpart the Fairchild 660 use single push-pull amplification stages with extremely high controlvoltages. Both variable-mu limiters are unique in that they use tubes for gain reduction as well asamplification. Compression takes place directly in the audio path, rather than being routed to a separatecircuit.Prior to the 660 and 670, Narma’s Gotham Audio Developments had built consoles and components forsuch luminaries as Rudy Van Gelder and Les Paul. Shortly after Paul asked Narma to build a limiter,Sherman Fairchild caught wind of the project, licensed the design, and hired Narma to come onboardas the company's chief engineer. After his stint at Fairchild, Narma relocated to the San Francisco BayArea and became vice president of Ampex, pioneers of multitrack recording equipment.PuigChild User Manual4