Universal Audio UAD Plug-Ins ver.7.5 - Manual (Page 165)

UAD Powered Plug-Ins Manual - 165 - Chapter 14: Fairchild Tube Limiter Collection
Input Gain versus Threshold
The amount of signal compression is determined by both the Input Gain and
Threshold controls. If one is increased and the other decreased, the compres-
sion characteristics won’t change much, but the distortion characteristics will.
The input control is located ahead of the tubes, directly “behind” the input
transformer. Therefore as the input control is increased, the input tube (the
gain-varying stage) is hit with more signal which can increase distortion
(which may or may not be desirable).
Tip: For less distortion with the same amount of compression, lower the input
gain and increase the threshold control.
Time Constant This 6-position switch provides fixed and variable time con-
stants (attack and release times) to accommodate various types
of program material. Positions 1-4 provide successively slower
behavior, and 5 and 6 provide program dependent response.
The values published by Fairchild for each position are in
Table 15 below. The actual measured times are a bit different, but the overall
trend is the same. The default value is Position 5.
Tip: When Sidechain Link is enabled and Controls Link is disabled, the Time
Constant settings of the two channels are interactive, which enables the ability
to have many other attack/release variations than those listed in the table.
Table 15. Fairchild Time Constants
Time Constant Attack Time Release Time
Position 1 200 microseconds 300 milliseconds
Position 2 200 microseconds 800 milliseconds
Position 3 400 microseconds 2 seconds
Position 4 800 microseconds 5 seconds
Position 5 200 microseconds Program dependent:
2 seconds for transients
10 seconds for multiple peaks
Position 6 400 microseconds Program dependent:
300 milliseconds for transients
10 seconds for multiple peaks
25 seconds for consistently high program level