rolls Stereo Direct Interface (DB24) This unit is a two channel isolation device designed to connect high impedance devices to low impedance. The unit is completely passive, and utilizes Rolls proprietary audio transformers for superior sound. A heavy duty steel chassis was chosen to provide maximum reliability when used in demanding live sound reinforcement applications. A variety of inputs are provided including stereo and mono 1/4-in , stereo RCA, and stereo 1/8-in (3.5mm).