This is not your usual headphone amp. The M903 is a highly reviewed “multi-purpose” unit that works as a DAC (four digital sources), preamp for two sources (one pair XLR and one pair RCA) and a pair of RCA line out and a pair of line outs that uses 1/4″ jacks and a top notch headphone amp for two headphones via 1/4″ headphone jack. So in terms of functionality, the M903 has nearly all the bases covered to function in a headphone only setup and a full size audio system. As a DAC, this is where it earned countless positive reviews for its outstanding clarity, detail retrieval and transparency. This was also clearly evident when you used it as a headphone amp too. Compared to the KingSound M-03 headphone amp that we recently sold, the M903 may cost three times more (at MSRP) but it also has a beefier sound to boot and add its many more features and flexibility, was the better buy if your budget extends to it.
Cosmetically, the unit looks really good. Some minor scuff marks here and there from use but but nothing major. We have the original box and a copy of the manual.