The Pro VLA II from ART is a dual-channel compressor/leveler that uses an opto-electrical design to provide smooth and musical dynamic range control. The unit features a mastering-quality audio signal path and a tube-based gain stage. Variable ratios that range from 2:1 to 20:1 allow the unit to work both as a compressor or a limiter. Metal rotary controls with detents provide for the adjustment of threshold and output level, along with variable and separate attack and release speeds. The front panel features large analog VU meters for each channel, while ten-segment, multi-colored LED arrays provide information on gain reduction. Back-lit push switches set whether either VU meter reflects input or output levels; select a straight wire bypass; and engage a link function, appropriate for stereo mastering. When the channels are linked, channel one controls act globally and the channel two output knob acts as a balance control. XLR and 1/4" TRS balanced input and output jacks are provided, along with a level selector to set the unit operating levels and metering to match either 4dBu or -10dBV systems. The unit is housed in a 2U space, rack-mountable steel chassis with a CNC routed, black anodized aluminum face panel. The Pro VLA II uses two hand-selected 12AT7 tubes and is designed for years of reliable operation in the studio and on the road.