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Grace Design m900 Compact, Portable Headphone Amp, DAC, and Preamp
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Grace Design m900 Compact, Portable Headphone Amp, DAC, and Preamp

(3 customer reviews)
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$462.00

Estimated delivery on 3 August - 14 September, 2025
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Items Included

  • Grace Design m900 Compact, Portable Headphone Amp, DAC, and Preamp
  • USB Wall Power Supply
  • 2 x USB Type-B Mini Cable: 6′ and 10′
  • Limited 5-Year Manufacturer Warranty
Key Features
  • Digital Inputs: USB, S/PDIF, TOSLINK
  • Supports Up to 192 kHz (TOSLINK: 96 kHz)
  • Two Zero-Ohm Headphone Outputs
  • Stereo RCA: Monitoring Control
  • High and Low Power Modes
  • DAC Filter Settings for Custom Playback
  • Display: 7-Segment LED
  • Large Rotary Encoder for Volume and Data
  • Includes Power Supply and USB Cables
  • 5-Year Limited Warranty

The Grace Design m900 is a compact, portable headphone amplifier, DAC, and preamp, well suited for audio professionals, music enthusiasts, or anyone looking for transparent playback from USB, S/PDIF, or TOSLINK sources. For small DAW setups, the m900 provides the same analog and DAC quality as Grace Design’s large monitor controllers, but in a rugged, portable, and surprisingly affordable unit.

The heart of the Grace Design m900 features the latest generation AKM 4490 chip, which includes 32-bit processing and support for sample rates up to 384 kHz or DSD256. 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 enhance any DAW interface with true reference-quality D/A conversion, headphone monitoring, and stereo speaker control.

The intelligent power supply design allows for two power operation modes, Low and High. Low power mode is derived from USB connection 1, which provides bus power along with data, allowing simple operation from a single connection to a computer. High power mode is available by connecting the included 2A USB DC power supply to USB connector 2, which provides additional power for high-impedance headphones.

The Grace Design m900 utilizes trans-impedance amplifier topology coupled to a zero-ohm output impedance driver for headphone performance that is spacious and transparent with a tight, enveloping low end, while the latest generation cross-feed circuit rounds out the design by emulating an acoustic listening environment in the headphones. The Grace Design m900 ships with a 2A USB power supply and two USB Type-B mini-cables (6′ and 10′.)

  • USB, S/PDIF and TOSLINK digital inputs, supports up to 192 kHz (TOSLINK up to 96 kHz)
  • Asynchronous USB interface for jitter free computer audio playback, supports up to 384 kHz PCM and DSD256
  • 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
  • Low power mode via USB Bus power
  • High power mode via included USB 2A power supply
  • Four different DAC filter settings to tailor playback performance to personal preference
  • Simple user setup menu for setup and calibration
  • Display: 7-segment LED displays level and setup menu information
  • Large rotary encoder for volume control and setup menu navigation
  • Made in the USA
  • 5-year transferable warranty
Category:
Connectors
Inputs
Digital Inputs: S/PDIF and TOSLINK
USB Power: Micro-USB 5 V, 2 A (high power input)
USB Data: Micro-USB 2.0 (for data, signal, bus power input)

Output
Stereo Line Outputs: RCA (L/R)
Headphone: 2 x 1/4″ / 6.35 mm
Display
7-segment LED
THD + N
THD+N 1 kHz, 22 Hz – 22 kHz BW
@1.0 V Out, No Load: <0.002%
@1.0 V Out, 32 Ohms Load: <0.010%
Intermodulation Distortion
Intermodulation Distortion SMTPE/DIN 4:1 50 Hz, 7 kHz
@1.0 V Out, No Load: <0.008%
@1.0 V Out, 32 Ohms load: <0.009%
Frequency Response ± 3dB
Fs=96 kHz: 0.5 Hz to 45.9 kHz
Dynamic Range
20 Hz to 22 kHz Bandwidth: 112 dB
20 Hz to 22 kHz Bandwidth and A-Weighting Filter: 115 dB
Output Noise
20 Hz to 22 kHz, Volume = 0-90: -106 dBV
A-Weighting Filter, Volume = 0-90: -109 dBV
20 Hz to 22 kHz, Volume = 90.5-99.5: -96 dBV
A-Weighting Filter, Volume = 90.5-99.5: -98 dBV
Crosstalk
100 Hz: <107 dB
1 kHz: <98 dB
20 kHz: <72 dB
Attenuation
Attenuation Range: 0 to -99 dB, 0.5 dB steps
Accuracy
Channel Tracking Accuracy: ±0.05 dB
Maximum Output Level
Maximum Output Level, No load
Low Power Mode: +14.1 dBV (5.1 V)
High Power Mode: +15.5 dBV (6.0 V)
Impedance
Headphone Output: 0.08 Ohms
Line Output: 47.5 Ohms
Lock Range
S/PDIF
44.1 kHz: 43870-45420 Hz
48 kHz: 46590-49220 Hz
88.2 kHz: 87760-90830 Hz
96 kHz: 93520-98430 Hz
176.4 kHz: 175700-181640 Hz
192 kHz: 187050-196380 Hz

TOSLINK
44.1 kHz: 43900-45410 Hz
48 kHz: 46590-49190 Hz
88.2 kHz: 87840-90830 Hz
96 kHz: 93520-97530 Hz

USB Supported Sample Rates: 44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384 kHz
Power Consumption
Max, High Power Mode: 8.0 W
Max, Low Power Mode: 2.5 W
Power Mode
Headphone Output Power
Low Power Mode 

1 Channel Driven
4 Ohms: 80 mW
8 Ohms: 140 mW
16 Ohms: 310 mW
20 Ohms: 350 mW
32 Ohms: 600 mW
50 Ohms: 560 mW
300 Ohms: 83 mW
600 Ohms: 40 mW

2-Channels Driven
4 Ohms: 22 mW
8 Ohms: 45 mW
16 Ohms: 90 mW
20 Ohms: 100 mW
32 Ohms: 175 mW
50 Ohms: 280 mW
300 Ohms: 83 mW
600 Ohms: 40 mW

High Power Mode

1 Channel Driven
4 Ohms: 925 mW
8 Ohms: 1800 mW
16 Ohms: 1900 mW
20 Ohms: 1575 mW
32 Ohms: 1020 mW
50 Ohms: 680 mW
300 Ohms: 115 mW
600 Ohms: 57 mW

2-Channels Driven
4 Ohms: 240 mW
8 Ohms: 490 mW
16 Ohms: 940 mW
20 Ohms: 1030 mW
32 Ohms: 950 mW
50 Ohms: 650 mW
300 Ohms: 115 mW
600 Ohms: 57 mW
Dimensions
4.0 x 5.3 x 1.8″ / 101.6 x 133.4 x 45.7 mm
Weight
Not specified by manufacturer
Packaging Info
Package Weight
2.325 lb
Box Dimensions (LxWxH)
10.35 x 10.3 x 4.5″

Based on 3 reviews

4.7 overall
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  1. Alex –

    The first thing you should note about this product is WHO makes it!

    Grace Design of Lyon, Colorado. For 20+ years these people have been making absolutely fantastic audio electronics, almost entirely professional gear for recording studios and topflight broadcasters.

    It is super clean and works off USB-2, etc. They include in the box an AC power device, but I find this device drives professional headphones (Sennheiser’s, for example) entirely adequately. No hum, no hiss. Just clean sound.

    Alex –

  2. Matthew –

    I’m not really a noob, but I don’t have a lot of experience with headphone equipment. I’ve been listening to headphones for about 6 years now, and I’ve been thru entry level and now midrange stuff.

    I am only using 2 headphones at this time, the Meze 99 classics, and Sennheiser hd 58x jubilee. I was previously using an Ifi nano idsd black label for amp and dac duties. So for the last two years I listened exclusively to this setup and enjoyed it for the most part. I always thought that Ifi boosted the bass on that unit.

    This Grace design m900 doesn’t have the boosted bass of the ifi nano. It also has a lot more tricks up its sleeve, with crossfade, 4 dac filter settings, and generally snappier dynamics. I like it, alot.

    Matthew –

  3. James –

    It works when it is bus-powered, but it shines when it is plugged in. It is clear, transparent, and surgical.

    James –

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