Universal Audio UAD POWERED PLUG-INS ver.6.1 - Manual (Page 269)

UAD Powered Plug-Ins Manual - 269 - Chapter 22: Fairchild 670
DC Bias DC Bias controls the ratio of compression as well as the knee width. As the
knob is turned clockwise, the ratio gets lower and the knee gets broader. The
threshold also gets lower as the knob is turned clockwise. The ‘factory cal’ tick
mark should be aligned with the screw slot “dot” for factory specification.
It would probably be more technically accurate to say that this control simply
changes the knee width, since no matter where it’s set the ratio always ap-
proaches true limiting eventually. However, the knee becomes so broad that
it becomes more practical to speak of the ratio changing, because for reason-
able (<25 dB) amounts of compression, this is the case.
Channel Input
Gain
This is a stepped attenuation control which always applies to left or right in-
put, regardless of the AGC control setting. The steps are approximately 1 dB
apart, with approximate unity gain coming at a value of 18, where the gain
is –0.33 dB.
Output Gain These controls always apply to the L and R channels, even when in Lat/Vert
mode. The labels around the knobs are in dB and the controls are stepped,
49-position controls, with each step being separated by 0.5 dB.
Controls Link This allows the two sets of controls for the interface to be linked. If the controls
are given an offset while unlinked and the controls are subsequently linked,
the offset is preserved up to the range of travel of the linked controls.