The Plinius pairs very well with the Obelisks. They do feel a little lost when it comes to rock music but are spectacular with jazz, strings, voice, and classical. I went with the Plinius on the recommendation of the Obelisk manufacturer, Shahinian Acoustics. Other amps that work well are the Creek 5350SE or Hafler. I strongly suggest taking a listen to them if you can.
Be well!
Matt