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.

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.

  • 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
  • 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 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   112dB
    20-22kHz bandwidth and A weighting filter   115dB
    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    
    Channel 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
      48kHz 46590-49190Hz
      88.2kHz 87840-90830Hz
      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

    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.

    m900 regulated USB power supply
    100-240VAC input / 5VDC 2A output
    US plug (Grace Part # T900)
    $14.00 US / domestic shipping incuded
    m900 regulated USB power supply
    100-240VAC input / 5VDC 2A output
    Euro plug (Grace Part # T901) $35.00 US / export shipping incuded