Grace Design: m303 Active DI

Whether working in a live venue, a professional studio, or at home, every recordist knows the importance of having a reliable DI unit. I use a DI on almost every session, so I was excited for the opportunity to try the Grace Design m303. As soon as I took it out of the box, I noticed its solid, durable build quality. The 1/4-inch aluminum chassis gave it a slightly heavier feel than other DIs I own, but considering how much I transport gear around, I appreciated its sturdiness. The m303 is a mono, phantom-powered active direct box, making it ideal for instruments with passive pickups. There is a convenient -13 dB Pad switch on the front panel for instruments with higher output levels. Between its Input and Thru jacks, is an indicator LED that lights up the signal exceeds -3 dB before clipping. I like having this visual cue, which allows me to easily see when I’m close to clipping. Furthermore, the m303 is designed with true galvanic isolation and incorporates an ISO/GND flip on the rear panel to prevent unwanted ground loops or noise from entering the signal. We all know how frustrating it can be when we have to chase down a hum (or ground noise) in the middle of a busy session, so this readily available feature is a big plus. All of this functionality is super handy, but there’s nothing ground-breaking here within the world of DI.

What interested me most upon receiving this unit was how it sounded. The m303 utilizes high-quality custom-wound Lundahl transformers, which are known for their transparency and low distortion. Using two identical recording chains, I set up an A/B test to compare the sound of the m303 against another DI I use frequently, my passive Radial JDI [Tape Op #49] with a Jensen transformer. I plugged an electric guitar into the JDI, and it sounded exactly as expected; clean and natural. Then I plugged into the m303, flipped on phantom power, and immediately noticed a remarkable clarity in the sound with the same transparency that I like about the Radial. The highs were detailed without being too harsh, and the mids and lows were robust without being muddy. Overall, the m303 delivered a balanced tone that brought the sound of my instrument to life without adding extra color. It also produced an exceptional richness to the sound of my bass guitar. The low end was deep, defined, and punchy. I had a live tracking session with a country band in the studio the next day, and I was excited to test out the DI further. It performed beautifully on various acoustic instruments with pickups, including dobro, fiddle, upright bass, and acoustic guitar. The m303’s pad came in handy for some of the louder instruments, and there was plenty of headroom to avoid clipping. The DI produced a very clean and open sound on all of these instruments. Again, I achieved a good amount of clarity in the mids, sparkle in the highs, and extension in the lows. On acoustic guitar, the transient response was impressive.

Having used the DI on a range of instruments now, I can tell the m303 will become my go-to workhorse in the studio. Its transparency and low distortion characteristics give me the flexibility I’m looking for when I want to capture an honest and true sonic picture. Although I primarily work in studios these days, I can see how the rugged build quality and isolation would make it perfect for live sound engineers. It’s easy to overlook the value of a high-quality DI unit, but the Grace Design m303 has reminded me just how essential it is when you want a truly accurate representation of your instrument.