The Radial Engineering Pro-Iso is a passive stereo line isolator designed to convert professional +4dB balanced line-level signals to unbalanced -10dB consumer audio devices. Its transformer-based circuit provides electrical isolation between connected equipment, helping eliminate hum and buzz caused by ground loops while also preventing stray DC currents from flowing between devices. The stereo dual-mono design makes the Pro-Iso suitable for recording, playback, computer interfacing, and other professional audio applications.

The Pro-Iso features balanced XLR inputs and unbalanced 1/4″, RCA, and 3.5mm TRS outputs for flexible connection to professional consoles, portable recorders, consumer audio equipment, and computers. A recessed level control provides convenient signal attenuation to help prevent the destination device from being overloaded, while the ground lift helps address unwanted noise caused by grounding issues. The unit delivers a 20Hz to 18kHz frequency response, 130dB dynamic range, and 0.005% total harmonic distortion at 1kHz.

Built into a rugged 14-gauge steel chassis, the Pro-Iso is designed for reliable use in professional audio environments. Its completely passive design requires no external power, making it easy to integrate into signal paths without adding another power requirement. Compact dimensions of 3.3″ x 5″ x 2″ make it convenient for desktop, rack, studio, and portable setups. The Pro-Iso is well suited for recording performances, converting balanced signals for consumer devices, and feeding computers or other unbalanced equipment while maintaining transformer-isolated signal integrity.

Product Specifications:

Product Type: Stereo Line Isolator

Audio Circuit Type: Passive, Transformer-Based

Transformer: Radial Transformer

Number of Channels: Stereo, Dual Mono

Frequency Response: 20Hz to 18kHz (+0dB/-3dB)

Dynamic Range: 130dB

Total Harmonic Distortion: 0.005% at 1kHz

Phase Deviation: 1.5 at 100Hz; 3 at 20Hz

Input Impedance: 1.3k Ohms

Output Impedance: 1.9k Ohms

Common Mode Rejection Ratio: -76dB

Maximum Input: +20dBu at 1kHz/1% THD+N

Features: Ground Lift, Level Control

Input Connectors: Balanced XLR

Output Connectors: 1/4″, RCA, and 3.5mm TRS Unbalanced

Power: Passive, No Power Required

Construction: 14-Gauge Steel Chassis

Primary Use: Line Isolation, Ground Loop Elimination, Recording, and Signal Conversion

Product Weight: 1.55 lbs.

Product Dimensions (L x W x D): 6.3″ x 5.0″ x 3″