VCA-Less Vactrol Opto-Compression Design Mastering Quality Audio Signal Path with Tube Gain Stage Enhanced Link Mode - While in stereo link mode, channel 1 level control acts as a master output level and channel 2 becomes a balance control between them, - optimizing the Pro-VLA II for use as a mastering tool Variable Threshold, Ratio & Output Controls LED Backlit VU Input/Output Level Metering LED Metering Indicates Both Average Level And Peak Hold Accurate Ten Segment LED Gain Reduction Metering +4dBu/-10dBu Mode Switch Optimizes Pro-VLA II For Interface with Professional OR Consumer Grade Components Active Balanced XLR And ﾼ-Inch Inputs & Outputs Toroidal Transformer Reduces Mechanical & Electrical Hum