If you want to go with Headamp, then go for the GS-1. It's head and shoulders above the Gilmore Lite (I have both) with better transparency and space. It works well with both Grado (I have RS1 etc.) and Sennheiser (I have HD600).
headphone amp
Looking for suggestions for a headphone amp that will drive either grado or sennheiser phones (low to high z). Something that retails for under a 1 k $. Have considered the Creek amps and the Grado amp - any experience with these (and what phones wre used with the amps), or other recomendations for amps in the 1 k $ retail and below would be appreciated?