A Voltage Controlled Amplifier (VCA) provides a means of easily controlling a group of faders, allowing the overall level of the grouped tracks to be brought up or down whilst maintaining the relative balance of the group members and retaining the individual track automation.

VCA Faders. VCA faders were introduced from Magix's high-end Sequoia DAW to Samplitude in Pro X2. ... All that a VCA fader does, in effect, is allow you to adjust the levels of multiple channel faders simultaneously.