DD Audio ZVL multi amplifier synching module.

DD Audio ZVL multi amplifier synching module.

The ZVL is a multi amplifier synching module designed to allow a user to link, strap, and tune the preamps of multiple amplifiers from a single module for precision control of large mobile audio systems. 
The ZVL was designed to work seamlessly with the new M Series amplifier’s ZVL INPUT, but it is universally compatible and will work with the DD Audio DM Series as well as other brands of Amplifiers.

Active signal processors capture the audio signal before it gets to the amplifier allowing you to modify the waveform to meet your needs. 
They require external power to operate, but provide a higher degree of adjustability than most amplifier preamps or passive (non powered) devices.