I have a pair of AKG 701 earphones that I'm using with a Schiit Audio Valhalla headphone amp with VERY nice sounding results. Before this I had a Musiland MD-10 DAC/Headphone amp and the music was very cold, and lean sounding. Seemed like everything had a metallic edge to it. The Valhalla was quite nice for way under $1000. Now the Valhalla is tube based but Schiit Audio does have a SS headphone amp called Asgard that you could take a look at.
good luck with your search.
good luck with your search.