Grace Design m900

Compact, Portable Headphone Amp / DAC / Preamp

Tiny Box, Huge Sound

The m900 is a portable, desktop-friendly headphone amplifier / DAC / preamp combo designed to give audio professionals and enthusiasts musical and transparent audio playback from USB, S/PDIF or TOSLINK sources. For small DAW studio setups, portable laptop editing or mixing rigs, or just pure playback enjoyment, the m900 provides the same analog and DAC quality as Grace Design’s large monitor controllers, but in a small, rugged, and surprisingly affordable unit.

Incredible DAC Performance

The m900 DAC uses the latest generation AKM 4490 chip, which features 32-bit processing and supports sample rates up to 384kHz PCM or 256x DSD. The USB interface operates in asynchronous mode allowing the m900 to be the clock master, which makes the system immune to USB bus jitter. S/PDIF and Toslink inputs allow the m900 to enhance any DAW interface with true reference quality D/A conversion, headphone monitoring, and stereo speaker control.

Intelligent Power Supply Design

An intelligent power supply design allows for two power operation modes – LOW and HIGH. LOW power mode is from USB connector #1, which provides bus power along with data, allowing the m900 to operate from a single connection to your computer. HIGH power mode is available by connecting the included 2A USB DC power supply to the USB connector #2, which provides additional power for harder-to-drive headphones.

Superb Audio Performance

Transimpedance amplifier topology coupled to a zero-ohm output impedance driver provides headphone performance that is incredibly spacious and transparent with a tight, enveloping low end. Grace Design’s latest generation crossfeed circuit rounds out the design by simulating an acoustic listening environment in the headphones. Familiar tracks become new again with surprising details, while audio production tasks like tracking, mixing, and editing happen faster and easier.

After many years of honing DAC and headphone amplifier designs, the m900 distills the best of what Grace Design has learned in a compact, rugged, and simple unit. Whether in the studio, on your desk, or on the road, the m900 will bring you closer to the music you love.

Features

• USB, S/PDIF and Toslink digital inputs, supports up to 192kHz (Toslink up to 96kHz)
• Asynchronous USB interface for jitter-free computer audio playback, supports up to 384kHz PCM and 256x DSD
• Dual zero ohm output impedance headphone outputs
• Unbalanced level-controlled outputs via RCA for connecting to a stereo monitor system
• Compact, portable chassis perfect for travel, desktop, or studio
• Mono mode, Left minus Right mode
• 6 monitoring modes: stereo, L&R swapped, left in both channels, right in both channels, left channel only, right channel only
• Channel balance adjustment
• Low power mode via USB Bus power
• High power mode via included USB 2A power supply
• 4 different DAC filter settings to tailor playback performance to personal preference
• Simple user setup menu for setup and calibration
• 7 segment LED display displays level and setup menu information
• Large rotary encoder for volume control and setup menu navigation
• Made in Lyons, CO USA
• 5 year transferable Warranty

• THD+N AT MAXIMUM VOLUME, 1KHZ, 22HZ-22KHZ BW
  • @1.0V out, no load: <0.002%
  • @1.0V out, 32 Ohm load: <0.010%
• INTERMODULATION DISTORTION SMTPE/DIN 4:1 50HZ, 7KHZ
  • @1.0V out, no load: <0.008%
  • @1.0V out, 32 Ohm load: <0.009%
• FREQUENCY RESPONSE +/-3DB
  • Fs=96kHz: 0.5-45.9kHz
• DYNAMIC RANGE
  • 20-22kHz bandwidth: 112 dB
  • 20-22kHz bandwidth and A weighting filter: 115 dB
• OUTPUT NOISE
  • 20-22kHz, volume=0-90: -106dBV
  • A weighting filter, volume = 0-90: -109dBV
  • 20-22kHz, volume=90.5-99.5: -96dBV
  • A weighting filter, volume = 90.5-99.5: -98dBV
• CROSSTALK
  • 100Hz: <107dB
  • 1kHz: <98dB
  • 20kHz: <72dB
• ATTENUATION RANGE
  • 0 to -99dB, 0.5dB steps
• CROSSTALK TRACKING ACCURACY
  • +/-0.05dB
• MAXIMUM OUTPUT LEVEL, NO LOAD
  • Low Power Mode: +14.1dBV (5.1V)
  • High Power Mode: +15.5dBV (6.0V)
• IMPEDANCES
  • Headphone Output: 0.08 Ohms
  • Line Output: 47.5 Ohms
• INPUT LOCK RANGE
  • SAMPLE RATE
  • LOCK RANGE
  • S/PDIF 44.1kHz: 43870-45420Hz
  • 48kHz: 46590-49220Hz
  • 88.2kHz: 87760-90830Hz
  • 96kHz: 93520-98430Hz
  • 176.4kHz: 175700-181640Hz
  • 192kHz: 187050-196380Hz
  • TOSLINK 44.1kHz: 43900-45410Hz
  • 60Hz 48kHz: 46590-49190Hz
  • 60Hz 88.2kHz: 87840-90830Hz
  • 60Hz 96kHz: 93520-97530Hz
• USB supported sample rates: 44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384kHz
• POWER CONSUMPTION
  • Max, High Power mode: 8.0W
  • Max, Low Power mode: 2.5W
• DIMENSIONS
  • 4″ x 5.25″ x 1.8″
• HEADPHONE OUTPUT POWER / LOW POWER MODE
  • OUTPUT POWER MW
  • Load Resistance Ohms
  • 1 Channel Driven: 2 Channels Driven
  • 4: 80: 22
  • 8: 140: 45
  • 16: 310: 90
  • 20: 350: 100
  • 32: 600: 175
  • 50: 560: 280
  • 300: 83: 83
  • 600: 40: 40
• HEADPHONE OUTPUT POWER / HIGH POWER MODE
  • OUTPUT POWER MW
  • Load Resistance Ohms
  • 1 Channel Driven: 2 Channels Driven
  • 4: 925: 240
  • 8: 1800: 490
  • 16: 1900: 940
  • 20: 1575: 1030
  • 32: 1020: 950
  • 50: 680: 650
  • 300: 115: 115
  • 600: 57: 57