Grace Design m303 Active, Fully-isolated DI Box

The Grace Design m303 is a high-performance, active DI (Direct Injection) box featuring galvanic isolation, a custom Lundahl transformer, ultra-low noise and distortion, and a rugged extruded aluminium chassis, engineered for professional stage and studio environments.

Superior Performance in Live Sound

The m303 delivers outstanding clarity and headroom, making it an essential tool for front-of-house engineers. It handles a wide range of sources—from keyboards and passive basses to acoustic guitars—with exceptional transparency and musicality. Its galvanically isolated active design eliminates ground loop noise while preserving dynamic content, ensuring reliable, clean signal integrity during demanding live performances.

Studio-Grade Clarity and Versatility

In the recording studio, the m303 provides detailed and lifelike direct instrument capture. With its robust low-frequency response and extended high-end detail, the unit enhances signal fidelity, making it ideal for further processing such as EQ, compression, or saturation. Its 1M ohm input impedance ensures optimal loading for passive pickups, preserving tonal nuance and transient accuracy.

The Lundahl Edge

Grace Design selected a custom-wound Lundahl transformer to meet the highest standards for audio quality. Known for their precision and low-noise performance, Lundahl transformers deliver superb low-end solidity and high-frequency transparency, making them the optimal choice for professional-grade DI applications.

Built to Endure

The m303 features a solid ¼” extruded aluminium enclosure that provides exceptional durability without compromising aesthetics. Designed and manufactured in the USA, the unit offers long-term reliability, backed by a comprehensive five-year warranty. Its advanced power supply architecture supports wide dynamic range, ensuring consistent operation under the most rigorous conditions.

• Active DI with galvanic isolation for clean signal transfer
• Custom-wound Lundahl transformer for superior audio quality
• Ultra-low noise and distortion with wide dynamic range
• Rugged ¼” extruded aluminium chassis for durability
• Deep, stable bass response and extended high-end clarity
• 1M ohm input impedance optimised for passive instruments
• Five-year warranty and made in the USA

This item, like everything we supply, comes with the complete support of our expert team. Our excellent technicians have been specifying, building and supporting studios for over twenty years. If you have any problems with installation, setup or everyday use, they’re never more than a click away, and always happy to help.

You can contact them here.