Grace Design m903 Reference Headphone Amplifier + 24-bit / 192kHz DAC


Highly reviewed headphone amplifier and DAC from Grace Design.

Beautiful condition and amazing all metal construction setting this apart from other headphone amps. Tested and working like it should.

More from Grace Design:

Built to Sound Amazing!
Replacing the venerable m902, the Grace Designs m903 is a stereo reference headphone amplifier and monitoring controller housed in a sleek 1U half-rack enclosure.

The m903 is designed to provide audio pros with an exceptional headphone amp along with stereo mains monitoring, whether from an analog or digital stereo source.

The m903 accommodates these different sources with rear panel XLR and RCA jacks, and both +4dBu and -10dBV sources are easily managed.

A pair of stereo TRS outputs allow two pairs of headphones to be driven by the m903. AES3, S/PDIF, and optical digital sources are accepted via rear-panel XLR, RCA and TOSlink connectors respectively.

Plus, there's a USB port allows you to pump your favorite pleasure-listening tunes through the m903 for a true audiophile listening experience.

But the m903 doesn't stop there. Two pairs of line outputs (balanced and unbalanced) on the rear panel allow the m903 to act as a high-end monitor controller and system preamp.

High-current transimpedance output amps can drive even the lowest impedance headphones, and a front panel rotary encoder provides precision level control of both headphone and line output levels, with level adjustments made in 0.5dB steps within a 95dB range.

Grace Designs m903 Headphone Amp/Monitor Controller Features at a Glance:
- Balanced and unbalanced analog inputs
- 24bit/192kHz digital stereo inputs- AES3, S/PDIF, TOSlink and USB
- High speed USB interface - completely asynchronous transfer mode allows for bit-perfect playback with zero interface induced jitter
- Driverless operation on Windows & Mac up to 96kHz/24bit
- Supports USB Class 2 audio specification for 192kHz/24bit operation on Windows & Mac (drivers needed for 192kHz operation under Windows)
- New generation DAC's and ultra low noise balanced current to voltage converter yields more m usical performance compared to the m902
- Mono mode for checking mix phase issues (or listening to Pet Sounds)
- s-Lock phase lock loop sample clock regeneration for ultra-low jitter and rock solid digital stability
- High-current transimpedance headphone amplifier circuitry built to effortlessly drive low impedance headphones
- Balanced and unbalanced variable level analog line outputs
- Improved power supply architecture isolates headphone power amplifiers, line amplifiers, DAC's and digital logic
- Precision level control with a 99.5dB range in 0.5dB steps
- Channel level matching accuracy of 0.05dB
- Improved x-feed circuit eliminates perceived loss of low frequency content
- Optional infrared remote control available
- Internal linear power supply with custom wound toroidal transformer
- Sealed gold contact relays used for all signal switching

Grace Design m903 Reference Headphone Amplifier + DAC ~ Manual

Click below to add our recommended matching cables from Kimber Kable, all brand new as SkyFi is an official Kimber dealer.

Kimber Kable - RCA Interconnects

Kimber Kable - XLR Interconnects

Kimber Kable - Coaxial Digital Interconnect

Kimber Kable - Optical Digital Interconnect

Kimber Kable - Digital AES/EBU (XLR Connector) Interconnect

Kimber Kable - Power Cords



Original Box





No (Originally Optional)


Yes - Power

Physical Condition


Working Condition


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