From the manufacturer: Wouldn't it be great if you could just turn up your amp for certain parts in your set? The MASTERMASTER system offers two switchable volume settings for every amp with an effects loop. It consists of two units: The small VCA UNIT (voltage controlled attenuator) is plugged into the effects loop of your amp and controls the volume in a way a simple potentiometer would do.It is optocoupler-based, the signal doesn't pass any active or mechanical elements. The REMOTE CONTROL UNIT can be placed anywhere (preferrably on your pedalboard) and controls the VCA unit via a regular guitar cable. Set both controls to the desired level and switch between the settings. This system offers many advantages over using a booster either before of after the preamp:– no alteration of the amp sound– no added noise, no risk of ground hum, no phase issues– no switch clicks or pops– fail safe (if unpowered, the amp runs on the set volume
