I would third the suggestion for the Primaluna Prologue Two. If you are moving from a mid-fi solid state amp, you will notice a huge improvement in midrange, warmth, dynamics, note decay/attack. Simply a fantastic amp.
It is also pretty much plug and play. It is a very easy amplifier to work with. Finally, it looks good and the build is top notch.
I usually don't appreciate the hype a lot of equipment gets but this one is for real.