BSS AR-133 DI Box

The BSS AR-133 is a compact, road-ready passive DI box built for live sound engineers and studio professionals who need transparent signal conversion without compromise. Its rugged aluminium extrusion case with polyurethane end-cheeks feels substantial in hand, and the arched design allows cables to route underneath for efficient cable management on crowded stages or in tight racks.

Signal Handling & Impedance Control

Three selectable input attenuation settings—0, -20, and -40dB—allow the AR-133 to handle everything from line-level keyboards to screaming hot guitar amplifier outputs. Input impedance automatically switches between 1 MΩ (at 0dB pad) and 47 kΩ (at -20dB or -40dB pad), ensuring optimal matching across a wide range of source impedances. Maximum input capability reaches +49dBu at the -40dB setting, while the ground-lift switch eliminates hum when balanced and unbalanced sources are mixed in the same system.

Audio Performance & Reliability

Distortion measures below 0.005% THD at 1kHz, and noise floor sits at -105dB unweighted (22Hz–22kHz), delivering pristine signal integrity even in noise-critical recording applications. Dual power options—+48V phantom power (with acceptance from +20V to +48V) and 9V battery backup—ensure the unit operates reliably whether mains phantom is available or not; the circuit automatically switches to battery if phantom power fails.

Key Features

• Input connectors: 1/4" jack and XLR socket (unbalanced)
• Output via XLR connector (transformer balanced)
• Parallel link output 1/4" jack for feeding to other equipment
• Three-position input attenuation: 0, -20, or -40dB
• Input impedance: 1 MΩ (pad at 0dB), 47 kΩ (pad at -20dB or -40dB)
• Maximum input: +9dBu (0dB), +29dBu (-20dB), +49dBu (-40dB)
• Maximum output: +8dBu into 600 Ohms or greater
• Phantom power supply from +20V to +48V; 9V battery backup with automatic switchover
• Ground-lift switch for hum elimination
• Distortion: <0.005% THD at 1kHz, 0dBu output
• Noise: <-105dB unweighted, 22Hz–22kHz
• Frequency response: 30Hz to 20kHz, +0dB/–1dB

The BSS AR-133 combines professional-grade audio performance, flexible impedance matching, and bulletproof construction in a package small enough to fit anywhere in your signal chain.