Check the listing for details. Radial Engineering PRO ISO Stereo Line Isolator +4dB/-10dB / Radial Transformer. Condition: New. Listed at 209.99 USD. The Radial Engineering PRO ISO stereo line isolator takes a high output +4dB line level signal from a mixing console and converts it so that it may be connected to low level unbalanced devices. In an effort to adapt to all of the variables, the output may be adjusted with a recessed set and forget level control. This makes it easy to interface professional audio gear with devices such as computer sound cards, iPods, or -10dB recorders. To reduce noise problems, the PRO ISO is equipped with an audio isolation transformer on each channel that helps eliminate hum and buzz caused by ground loops. Connections are straightforward: inputs are standard balanced XLR female while outputs include choice of stereo RCA, 3.5mm or standard 1/4".