@mlapenta , I recently moved from a Cayin HA-3A to the Black Ice Audio Aries DAC/Amp/Pre, and am really happy with the performance it offers with a huge range of tuning options (channel balance, gain adjustment, independent left and right high frequency control, bass adjustments) and it responds very well to 6SN7 tube swapping.
I could see this unit getting most off of the gear swapping merry-go-round in your price range. It should offer enough adjustment to dial in any headphone to your liking.