I decided to go with the HD650s as a first venture into the Sennheiser world of headphones
Will wait for break in (100+ hrs?) before forming a more precise opinion, and see how they contrast vs. the AQ NightHawks and Audeze LCD2s.
Next in line will be a matching tube amp, for a different taste to the Burson V2+, likely a Woo Audio following some good advices from Tony and Serge
