Radial Highline Mono 1-Channel Passive Line Isolator

The Sanctuary Perspective

The Radial Highline Mono is a compact, single-channel passive line isolator engineered to eliminate ground loop hum, buzz, and system noise in professional guitar rigs, stage setups, and studio signal chains. Designed for single-channel line-level applications—such as isolating a mono pedalboard output, a digital modeler feed, an amp fx loop connection, or a single synthesizer output—the Highline Mono delivers absolute galvanic isolation without degrading your instrument's natural tone. Powered by a custom-wound Radial Eclipse nickel-core transformer, it transparently handles hot line-level signals with ruler-flat frequency response and zero active distortion.

Product Intelligence & Signal Integrity Profile

• Best For: Single-Amp Rigs, Pedalboard-to-FOH Mono Connections, Digital Modeler Outputs, FX Loop Isolation, and Studio Line-Level Signal Isolation.
• Sound Character: 100% transparent and uncolored across a wide 10Hz to 40kHz bandwidth, with zero added active noise floor and precise phase response.
• Compared To: Offers significantly higher input headroom (+22dBu) and wider frequency linearity than standard budget DI/isolators, utilizing high-nickel core Eclipse transformers engineered specifically for high-level audio feeds.
• Sanctuary Expert Note: "When you connect your pedalboard or amp modeler into a venue's PA system or a second amplifier and immediately get a loud 60-cycle ground buzz or digital noise, the Highline Mono is the instant, hassle-free fix. Plug it in, hit the ground lift if needed, and enjoy dead-quiet performance."

Key Features & Engineering Highlights

• Custom Radial Eclipse Nickel-Core Transformer: Features a premium custom-wound transformer that completely isolates audio signal paths to stop ground loops while preserving linear response from 10Hz to 40kHz.
• High Input Headroom: Capable of accepting line levels up to +22dBu without transformer saturation, making it perfect for hot line outputs from preamps and modern digital modeling units.
• Selectable Ground Lift Switch: Instantly disconnects the audio signal ground path to eradicate 60-cycle hum, buzz, and stray electrical currents.
• Versatile I/O Options: Equipped with balanced 1/4" TRS input and output jacks along with a 3.5mm mini-stereo pass-through port for effortless integration onto dense pedalboards or rack setups.
• 14-Gauge Steel Shell: Built inside Radial's legendary "book-end" heavy-duty steel chassis with an internal I-beam frame that protects the internal PCB from stage mechanical stress.

Technical Specifications

• Audio Circuit Type: Passive, Transformer-Coupled Line Isolator
• Number of Channels: 1 (Mono)
• Transformer: Custom Radial Eclipse Nickel-Core
• Frequency Response: 10Hz – 40kHz (± 0.5dB)
• Dynamic Range: > 135dB
• Maximum Input Level: +22dBu @ 1kHz
• Total Harmonic Distortion (THD): 0.002% @ 1kHz (+4dBu)
• Input Impedance: 10kΩ Balanced / Unbalanced
• Output Impedance: 10kΩ Balanced / Unbalanced
• Inputs: 1 x 1/4" TRS, 1 x 3.5mm TRS
• Outputs: 1 x 1/4" TRS, 1 x 3.5mm TRS
• Switches: Ground Lift
• Power Requirement: None (100% Passive Operation)
• Chassis: 14-Gauge Steel Shell with Powder Coat Finish