In his bimonthly column, "
The Fifth Element," John Marks has tried to identify pro-audio components that would be of interest to audiophiles. In his
June 2005 episode, John wrote about Grace Design's m902 D/A headphone amplifier ($1695), the Colorado company's replacement for the
901, which had long been a favorite of his. Changes include: the handling of single-wire sample rates of up to 192kHz; unbalanced analog outputs, controlled by the front volume control, to allow the unit to be used as a preamplifier; a cross-feed processing circuit licensed from
www.meier-audio.de; power-supply revisions; and the provision of a USB digital input, in addition to S/PDIF, AES/EBU, and TosLink.