m900 headphone amp / DAC

m900

Compact, Portable Headphone Amp / DAC / Preamp

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 our large monitor controllers, but in a rugged, portable and surprisingly affordable unit.

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 to any DAW interface with true reference quality D/A conversion, headphone monitoring and stereo speaker control.

Sound on Sound Awards 2021

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 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.

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. Our latest generation crossfeed circuit rounds out the design by simulating an acoustic listening environment in the headphones. Familiar tracks become new again with surprise details, while audio production tasks like tracking, mixing and editing happen faster and easier.

After many years of honing our DAC and headphone amplifier designs, the m900 distills the best of what we’ve 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.

04/2018 – m900 Firmware v2.3 Available

Implements the following new features: Mono Mode, Left minus Right, Channel Balance adjust, Monitoring Modes (stereo, L&R swapped, left in both channels, right in both channels, left channel only, right channel only). Visit our support page for download and installation information.

I guarantee even hard-working audio pros will be tempted to start listening to music for pleasure with the m900, it’s performance at super-low monitoring levels is really outstanding. -Nigel Jopson, Resolution read full review

The m900 is small, light, and portable. Most importantly, it will drive a range of headphones to comfortable listening levels and beyond, and you can trust what you hear. Take it home, and it becomes the hub of a computer-based music system, feeding headphones and either a power amp or powered speakers. And it’s built out of metal and looks good. What’s not to like? – Tom Fine, TapeOp read full review

At this price, there is no headphone box/DAC that touches the m900 in features, support of sample rates, and stunning audio quality. You can easily carry it in a backpack which makes it even better. The m900 from Grace Design is a must-have for desktop mixer/producers on the go. – Kevin Becka, MIX read full review

The Grace Design EON and STANDARD Warranties

We back up everything we make with either our unrivaled 20 year EON limited warranty, or the 5 year standard limited warranty. These represent the best coverage in the business and prove our commitment to the quality, serviceability and long term value of Grace Design products.

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
Specifications
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=96kHz0.5-45.9kHz
Dynamic Range
20-22kHz bandwidth112 dB
20-22kHz bandwidth and A weighting filter115 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 Output0.08 Ohms
Line Output47.5 Ohms
Input Lock RangeSample RateLock Range
S/PDIF44.1kHz43870-45420Hz
48kHz46590-49220Hz
88.2kHz87760-90830Hz
96kHz93520-98430Hz
176.4kHz175700-181640Hz
192kHz187050-196380Hz
TOSLINK44.1kHz43900-45410Hz
60Hz48kHz46590-49190Hz
60Hz88.2kHz87840-90830Hz
60Hz96kHz93520-97530Hz
USB supported sample rates44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384kHz
Power Consumption
Max, High Power mode8.0W
Max, Low Power mode2.5W
Dimensions
4″ x 5.25″ x 1.8″
Headphone Output Power / Low Power ModeOutput Power mW
S/PDILoad Resistance Ohms1 Channel Driven2 Channels Driven
48022
814045
1631090
20350100
32600175
50560280
3008383
6004040
Headphone Output Power / High Power ModeOutput Power mW
S/PDILoad Resistance Ohms1 Channel Driven2 Channels Driven
4925240
81800490
161900940
2015751030
321020950
50680650
300115115
6005757
Power Modes

Low Power, USB input – One USB cable from the computer to the m900 #1 USB input. m900 receives power and audio from the computer.

High Power, USB input – One USB cable from the computer to the m900 #1 USB input and one USB cable from the external 2A DC power supply to the m900 #2 high power DC input connector. The m900 receives audio from the computer and receives power from the external DC supply.

Low Power, S/PDIF or TOSLINK input – One USB cable from a standard USB power source (computer or 0.5A USB power supply) connected to the m900 #1 USB input. TOSLINK or S/PDIF input connected. (This would be an unusual setup where you don’t have access to a high power DC power supply.)

High Power, S/PDIF or TOSLINK input – One USB cable from the 2A DC power supply to the m900 #2 high power DC input connector. TOSLINK or S/PDIF input connected. m900 receives audio from TOSLINK and power from the external DC supply.

Self Powered Mode – This mode is for connecting your mobile device (iOS, android) to the m900. Mobile devices generally cannot provide any power. In this mode the m900 will report that it is self powered. To enter self powered mode, first connect the USB cable from the external 2A DC power supply to the m900 #2 high power DC input connector, then connect your device to the m900 #1 USB input. For iOS, you will need the ‘Apple Lightning to USB Camera Adapter’, for supported Android devices you will need an ‘On The Go’ USB cable.

Find a dealer near you

Contact Us

We're not around right now. But you can send us an email and we'll get back to you, asap.

Not readable? Change text. captcha txt