GRACE design m303 [Stereo Active DI]

A stereo active DI box with next-generation sound quality performance.

The m303s is a completely new and innovative "active/fully isolated" stereo DI box. It delivers next-generation audio performance for all live stage and studio applications.
GRACE design's signature high-end power supply design delivers incredible headroom and dynamic range. Custom-wound Lundahl transformers enable the output of the clearest bass and most delicate treble ever.
The beautiful, elegant blue casing features a 1/4-inch thick extruded aluminum chassis, providing robust durability for long-term use.


■ As a high-quality stereo DI for live stage use.
The m303s is the highest-quality stereo DI box available to FOH engineers.
The unparalleled clarity and detail reproduction ensure that large-scale live productions maintain a superb sound.
The open, musical sound is perfect for any source on stage, including bass, acoustic guitar, and keyboards.
Furthermore, the reliability of Grace Design products, which have an established reputation, will satisfy venues and stage crews for an extended period.

■ For use as a studio DI for high-quality recording.
The m303s offers the highest quality sound as a stereo DI for studio recording.
The sound becomes vibrant and detailed, and the clarity of the low frequencies is perfectly maintained.
This allows for more effective processing in subsequent stages (saturation, compression, EQ, etc.), resulting in better recording and mixing.
This is a new standard for high-quality stereo DI boxes, something musicians and engineers have been searching for.

■Features a custom-wound Lundahl transformer.
Lundahl is a world-renowned manufacturer of high-end transformers for professional audio, making them the best choice to meet the high sound standards pursued by the m303s.
Two sets of custom-wound Lundahl transformers deliver astonishing bass clarity and beautiful treble detail with exceptionally low noise performance.

-Main product specifications-
● Stereo (dual mono) version of the m303 ● Active DI powered by phantom power
● Complete galvanic isolation ● Equipped with a custom-made Lundahl transformer, high-nickel core, and magnetic shielding ● Achieves ultra-low distortion characteristics of -100dB@1kHz and -80dB@50Hz or less ● Ultra-low noise (-118dBu, A weighting)
● Ultra-wide frequency response (20-80kHz) and dynamic range (124dB)
● Excellent low-frequency headroom: THD+N @50Hz -80dB (0.007%)
● 1MΩ input impedance: Suitable for line and pickup signals ● Peak indicator: Lights up 3dB before clipping ● Efficient phantom power design: Consumption is only 4mA
● Through-out output ● Input PAD switch (13dB): for high-level signals ● Full ESD (electrostatic discharge) and RFI (radio frequency interference) protection ● High-quality gold-plated toggle switch ● Durable 1/4-inch thick extruded aluminum chassis and flush-mount connectors

-Advantages of the m303s-
● Stereo DI specification ● Transparent sound quality and musicality unique to Grace Design ● Active design with perfect galvanic isolation ● Uses Lundahl's world-renowned custom transformer ● Extremely low distortion and noise, wide dynamic range ● Deep, stable bass response ● 1MΩ input impedance ● Designed for long-term durability ● Made in the USA

■Gain
Pad Off, 13.6k Ohm load: -6dB
Pad On, 13.6k Ohm load: -19dB

■Frequency Response
± 0.2dB (50Ω source, 13.6k load): 82Hz-27kHz
± 3dB (50Ω source, 13.6k load): 20Hz-80kHz

■Built-in High Pass Filter
2nd Order, Bessel: -3dB 20Hz

■THD+N 20Hz-20kHz BW
-10dBu out, 1kHz: -102.8dB (0.00072%)
-10dBu out, 50Hz: -83dB (0.0073%)
-10dBu out, 25Hz (10Hz-20kHz BW): -72dB (0.023%)

■Intermodulation Distortion -10dBu Out
SMPTE/DIN 1:1 (50Hz, 7kHz): -106dB (0.0005%)
SMPTE/DIN 4:1 (50Hz, 7kHz): -99dB (0.0010%)

■Noise? Output Level 20Hz-20kHz
Pad Off, 50Ω source: -116.2dBu
Pad Off, Input disconnected (equivalent to 330pF source): -112.3dBu
Pad On, 50Ω source: -113.1dBu
Pad On, Input disconnected (equivalent to 330pF source): -113d.0Bu

■Noise? Output Level A-weighted
Pad Off, 50Ω source: -118.6dBu
Pad Off, Input disconnected (equivalent to 330pF source): -114.9dBu
Pad On, 50Ω source: -115.5dBu
Pad On, Input disconnected (equivalent to 330pF source): -115.2dBu

■Phase Deviation
10°: 97Hz-7.5kHz

■Maximum Input Level (0.1% THD+N)
1kHz, Pad Off: 14dBu
1kHz, Pad On: 27dBu

■Maximum Output Level (0.1% THD+N)
Balanced, 1kHz, 13.6kΩ Load: 8dBu
Balanced, 1kHz, 3.65kΩ Load: 7.3dBu

■Impedance
Input Pad Off: 1MΩ
Input Pad On: 115kΩ

■Output: 330Ω

■ Power Supply
48V Phantom Power, IEC 61938 4mA max

■Weight: 655g
■SIZE: 134mm(L) x 100mm(W) x 44mm(H)