DigiDesign Bomb Factory, Manual

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Chapter 8: Fairchild Plug-ins 23
chapter 8
Fairchild Plug-ins
(TDM, RTAS, and AudioSuite)
This chapter describes the following Fairchild
plug-ins:
• Fairchild 660 (see “Fairchild 660” on
page 23)
• Fairchild 670 (see “Fairchild 670” on
page 25)
Fairchild 660
(TDM, RTAS, and AudioSuite)
Re-introducing the undisputed champion in
price, weight, and performance: the $35,000,
one-hundred pound, Fairchild 660.
Bomb Factory’s no-compromise replica captures
every detail of this studio classic.
How the Fairchild 660 Works
Designed in the early 1950s, the Fairchild 660 is
a variable-mu tube limiter. Variable-mu designs
use an unusual form of vacuum tube that is ca-
pable of changing its gain dynamically.
The result? In addition to featuring a tube audio
stage like the LA-2A, the Fairchild actually
achieves gain reduction through the use of
tubes!
The heart of the Fairchild limiter—a 6386 tri-
ode—is one such variable-mu tube. In fact, four
of these tubes are used in parallel. A key part of
the Fairchild design, it ensures that the output
doesn’t get darker as the unit goes further into
gain reduction, and also reduces distortion as
the tubes are biased further into Class-B opera-
tion.
Bomb Factory Fairchild 660
Tubes, wires, and iron