Universal Audio UAD Plug-Ins ver.7.5 - Manual (Page 168)

UAD Powered Plug-Ins Manual - 168 - Chapter 14: Fairchild Tube Limiter Collection
Keep in mind there are no hard and fast headroom rules. Feel free to exper-
iment with the various positions of the HR control regardless of the audio
source. If it sounds good, use it!
Note: The HR control does not exist on the Fairchild 670 Legacy. On the
hardware unit, the Zero screw (as displayed in the Fairchild 670 Legacy) ad-
justed the meter pointer to compensate voltage fluctuation and component
wear.
Balance Balance controls the bias current balance. It always controls one
channel of the compressor, regardless of what the nearby Meter
Switch is set to. The point of perfectly calibrated bias currents is
achieved when the screw slot is at the 12 o’clock position (the de-
fault value). At this setting, the amount of additive signal deflection (“thud”)
which happens due to an attack is minimized. Setting this control counter-
clockwise from this position results in a thud of one polarity on transients, and
going clockwise produces a thud of opposite polarity.
Tip: Click the “BAL” text label to return the control to the default position.
Note: To avoid the DC settling artifacts that can result when adjusting Bal-
ance, automating this control is not recommended.
Sidechain Filter The Sidechain Filters (one each for the Left/Lat and
Right/Vert channels) control the cutoff frequency of
a low-cut filter on the compressor's control signal
sidechain. They have a slope of 12 dB per octave.
The available range is 20 Hz to 500 Hz, and Off.
The default value is Off.
Tip: Click the OFF label to disable the sidechain filter.
Removing low-frequency content from the sidechain can reduce excessive
gain reduction and/or “pumping” on bass-heavy audio signals without reduc-
ing bass content of the audio signal itself.
Auditioning the Sidechain Filter
To quickly switch back and forth between OFF and the last set value, click the
OFF label. This feature is handy for comparing the filtered and unfiltered
sidechains.
Note: The Sidechain Filter affects the control signal of the compressor only.
It does not filter the audio signal.