The Radial Highline is a passive line isolator designed to connect guitar and amp modelers to a mixer, PA, or recording system, especially useful for live touring and studio applications. It uses a precision-wound Jensen 1:1 transformer to preserve signal strength and tone while providing galvanic isolation that reduces ground-loop hum and blocks phantom power. The device converts an unbalanced ¼" signal into a balanced XLR output, making it suitable for long cable runs without encountering noise or signal degradation. A sum switch enables stereo sources to be summed to mono when needed, and a ground-lift switch further helps eliminate unwanted noise. Built in a rugged steel chassis with a pedalboard-friendly form factor, the Highline is a passive, plug-and-play solution that requires no external power and delivers reliable, transparent audio performance.