The Kingrex Headquarters HQ-01 is a headphone amplifier unit that retails for about $895. It is single ended, solid state, and two case design. I have listened extensively to a review sample for the past three or so months. In my opinion, the unit compares well to the Graham Slee Solo and is...

KingRex asked me to review their new top-end headphone amp, the “Headquarter” HQ-1. This amp sells for about $850, which isn’t crazy expensive, but isn’t exactly cheap either, and does put it in direct competition with some very fine amps, both tube and solid state. According to KingRex, the...