Radial Engineering HIGHLINE STEREO Stereo Passive Line Guitar Amp IsolatorAmp simulators are more popular than ever, but they present a unique set of problems for guitar and bass players who want to interface them with a PA system. While amp sims can produce line level outputs, they often have " unbalanced connectors that aren't designed for long cable runs, and they encounter hum and buzz from ground loops when connected directly to the PA. The Radial Highline Stereo is the ultimate line isolator for stereo amp simulators