You make it hard because your speakers are a total unknown. The Aragon is probably the week link in your system but knowing nothing about your speakers I can't really recommend a different amplifier.
Solid state on a Power Amp. I am open to either on a Pre. This is #1 for reliability purposes and #2 I think that since the early 1990's there have been big improvements in solid state so a good SS component today is significantly improved (?). There are lots of tube stuff I salivate over (Manley, VAC, VTL etc)but out of my league. I would consider Pass. In fact I have been considering the X150. I was considering the Plinius but some have said they run even hotter than the Pass stuff and I have concerns with reliability/servicing of an item from overseas. At least I can get Pass equipment serviced.