ART Pro VLA II Tube Compressor
The Pro VLA by ART is a tube driven Vactrol-based Compressor/Leveling amplifier designed to excel in any professional audio application, including tracking, mixing, mastering, live sound or broadcast situations. By using an opto-electronic design, (as opposed to a more typical VCA driven level detection circuit) the Pro VLA II allows more compression to be added to an audio source with a more natural, musical sounding output and virtually transparent dynamic leveling. This VCA-less design coupled with a 12AT7 vacuum tube in the gain stage makes the Pro VLA II tube compressor the ideal dynamic control device for critical studio and live sound applications.

These are the differences between the Pro VLA and the Pro VLA II:

1. Enhanced Link mode
In link mode, CH1 output control acts as a master output level and CH2 becomes a Balance control. This optimizes the Pro VLA II for use as a mastering processor.

2. Active balanced outputs. The old VLA has balanced outputs that have 6dB more gain than when using them in the unbalanced mode. This shows up as an error when using the VU meter to compare the input and output level.

3. LED output meter.
a. Always monitors the output level allowing the user to view Both input and output levels at the same time.
b. LED meter indicates both average level plus Peak hold.

4. Attack and Release knobs vs. switches. The Old VLA compressor has switches that allow the user to adjust the attack time between "Fast" (~1mSec) and "Normal" (~10mSec). The release switch can be set to "normal" (200mSec) and "Auto" (program dependant, but rather long an average).
a. Attack time as ranges from .25mSec to 50mSec
b. Release time ranges from 0.15Sec to 3Sec. (This is program dependant at shorter release rates).
c. Improved detector that lowers low frequency distortion at fast release rates.

5. Improved package
a. Rounded front panel machined to countersink all knobs and level meters.
b. Re-enforced ears.
c. Led lit switch caps.
d. Heavier chassis and cover ruggedized for longer life on the road.

6. Lower noise.
a. +4dBu/-10dBv mode switch optimizes the unit for Pro OR consumer operating system levels.
b. Toroidal transformer reduces mechanical and electrical hum.
c. Tweaked Tube circuit for better dynamic range.
d. Increased transformer shielding.

7. Increased ranges on Threshold and Output gain. This allows the user a wider range of operation.
a. Old threshold = -20 to +15, New Threshold range = -30dB to +20dB.
b. Old Output gain max = +10dB, New output Gain = +20dB

8. LED lit VU meters. No more dark meters due to blown out bulbs.

9. All of the pots have detents.
a. Imparts a more professional feel.
b. Makes settings more repeatable.