Grace Design

Now available with balanced line outputs!
The m902 is built upon the remarkable success of the venerable model 901 headphone amplifier, with the addition of many new and essential features. It is designed to be an invaluable tool for any critical audio application for which reference quality headphone amplification is required.

Professionals and audiophiles alike will be simply floored by the m902’s latest generation, high performance 24/192 DAC, which includes our unique s-LockTM dual stage PLL (Phase Lock Loop) for extremely low intrinsic jitter and rock solid digital performance. A full complement of analog and digital inputs are available (AES3, S/PDIF, TOSLINK and USB), which are all selectable via a front panel rotary switch.

The core of the m902 is our meticulously designed high-current transimpedance amplifier circuitry, which is designed to effortlessly drive even the lowest impedance headphones and provide the high-resolution and low-level ambient detail for which all Grace Design products are famous. Familiar recorded material becomes at once transparent and alive, and critical details in editing and mastering become obvious and easy to manipulate.

The m902 includes a crossfeed circuit, or XFeed, which simulates the natural acoustics of a loudspeaker listening environment and HRTF (Head Related Transfer Functions). This circuitry, designed by Dr. Jan Meier, can significantly improve imaging, while reducing listening fatigue when using headphones.

The m902 also cleverly adds stereo unbalanced analog line outputs for connection to studio monitors or any speaker system, allowing it to double as an elegantly simple high fidelity monitor controller or even a purist audiophile preamplifier / DAC.

As the logical update of the model 901, the new m902 reference headphone amplifier stakes its claim as the final word in reference headphone amplification and as the new must have tool for audio playback in any environment.

Owner's manual

Features

balanced and unbalanced analog inputs
24bit/192kHz digital stereo inputs- AES3, S/PDIF, TOSLINK and USB (USB input supports 16 bit/44.1 and 48k only)
s-LockTM 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
variable level balanced or unbalanced analog outputs for studio monitors
all electrical and mechanical design elements maximized for absolute purist, audiophile performance
precision level control with a 95dB range in .5 dB steps
channel level matching accuracy of 0.05dB
crossfeed circuitry (XFeed) for improved headphone imaging
optional infrared remote control available
internal linear power supply with custom wound toroidal transformer
no electrolytic capacitors in the signal path
highest quality metal film resistors used throughout
sealed gold contact relays used for all signal switching
five year warranty on parts and labor

Specs

Gain
Normal Mode +0dB
Boost Mode +10dB

Frequency Response
@ 0dBu out +/- .25dB 22Hz - 120kHz
@ 0dBu out +/- .5dB 12Hz - 260kHz
@ 0dBu out +/-3dB 4Hz - 600kHz

Maximum Output Level
@1kHz, 50 Ohm load +21.4dBu (9.11Vrms)

Impedance
INPUT 106K Ohms balanced
INPUT 53K Ohms unbalanced
OUTPUT 1 Ohm

Dynamic Range
@ 0dB gain 116dB
@ -10dB gain 119dB

THD+N
+10dBu out, 50 Ohm load SMPTE 4:1 <0.01%
Headphone +10dBu out, 50 Ohm load <0.08%
Line Out +10dBu out <0.002%

Attenuator Level Matching
24 position switch <0.05dB
Attenuator Range 99.5dB

D/A Specifications
Input sample rate 32, 44.1, 48, 88.2, 96, 176.4, 192kHz

THD+N
44.1kHz, 24-bit, 1kHz, +20dBu out <0.002%

Noise Floor
0dB gain, 22-22kHz -94dBu
0dB gain, A-weighted -97dBu

Power Requirements
115VAC .16A
230VAC .08A

Dimentions 8.5w x 8.25d x 1.7h
Weight 5 lbs/2.2kg

Single Ended Output Option.

Balanced Output Option. Ask about our Custom Balanced TRS to XLR cables