
The dbx 563X units aka The Silencer were originally designed for use with tape recorders to remove tape hiss from recordings and they do it very well, however we do not use tape as much now as we used to but the units can also be used to remove noise from other sources.
If you have another noisy items such as a synth or any other instrument you can use the 563X to reduce the line noise.
The 563X units can be used singly or as a stereo pair, it stereo one can be used as a master the others as a slave switchable from the back of the unit