Grace Design m900 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.
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.