Pre Amps or amps for headphones

I am only semi-knowledgeable on higher end audio, but I have heard that Melos makes a Pre Amp (SHA gold reference (and ? ma-200 gold plus)) that is great for headphones. I presently have a HeadRoom Supreme that I use with Sennheiser 580's, but I want to upgrade. Any discussion and advise/opinions will be greatly appreciatged. Others that I have considered are: CLASSE CP 50 pre- Silver Audible Illusions L-1 AUDIO NOTE M-2 Krell but I don't know how they compare with a primary use for headphones. I also have Esotric Audio Research 100 watt mono block amps, a VTL line preamp and ACOUSTAT 2+2 speakers that I might also use the pre amp with, but my primary interest is for a headphoone set up. Thank you in advance for your assistence. bjd