ART PDB4 - 4-Channel Passive Rack Mount DIThe PDB4 is a four channel passive direct box that features four quality fully transformer isolated direct boxes in a 1U 19 inch rack mount chassis. Inputs and outputs of each of the four channels are isolated to maximize channel separation. Transformer isolation on each output helps to eliminate system ground loops. It is a rock solid, roadworthy interface for connecting outputs of electronic musical instruments (or other audio sources) to the