Boulder, Colorado (December 27, 2004)–Grace Design has begun shipping production versions of its new m902 reference headphone amplifier, which was debuted at the recent AES show in San Francisco. The m902 is a stereo reference headphone amp and monitoring controller housed in a 1U, half-rack enclosure whose industrial design mirrors that of the company’s m904 and m906 monitoring systems.
The m902 has been designed to provide audio pros in music, post and live sound with exceptional headphone as well as stereo mains monitoring, whether from an analog or digital stereo source. The m902 provides balanced and unbalanced stereo analog inputs via rear panel XLR and RCA jacks. Both +4dBu and -10dBV analog sources are accommodated. A pair of front panel, parallel-wired 1/4-inch TRS outputs are included to allow two headphone pairs to be used simultaneously. The m902 also adds a pair of line outputs on the rear panel for connection to a stereo pair of monitors, allowing the system to also perform as a high-end system preamp.
The m902 employs high-current, transimpedance output amplifiers optimized for driving even the lowest impedance headphones. A front panel rotary encoder provides precision level control of both headphone and line output levels and level adjustments are made in 0.5dB steps within a 95dB range. Channel to channel level matching is a low 0.05dB. AES3, S/PDIF and optical digital sources are accepted via rear-panel XLR, RCA and TOSLINK connectors respectively. As an added convenience, a USB input (16-bit, 44.1 – 48kHz operation) is supplied for users who desire a reference quality listening experience while connected to their computer.
A front panel rotary switch selects between all analog and digital sources, and a 4- LED array is provided to show valid digital source sample rates between 44.1 and 192kHz. A high performance 24-bit DAC, which includes Grace’s unique s-Lock TM dual stage PLL (Phase Lock Loop) is utilized for conversion and provides exceptional results with extremely low intrinsic jitter.
The m902 also includes an exciting new feature (Xfeed) that simulates the acoustics of a loudspeaker listening environment which significantly improves imaging while reducing listening fatigue when using headphones. This feature employs carefully designed signal cross-feed, filtering and delay circuits to simulate HRTF (Head Related Transfer Functions).
The m902 incorporates an internal linear power supply, built with a custom wound high-current, low-noise 30 watt torroidal power transformer. Only the highest quality 0.5 percent metal film resistors are used throughout and there are no electrolytic capacitors in the signal path. Sealed gold contact relays are used for all signal switching.
Finally, the m902 is equipped with an infrared sensor which allows remote operation of numerous system parameters when connected to the (optional) m902RCU remote control.
The m902 has an SRP of $1,695 (U.S.) and the optional m902RCU remote is priced at $125 (U.S.).