I used a Levinson 23 with Thiel 3.5's several years ago.
I never could tame brightness or harshness in the system,
which I think was due more to the speakers than the amp.
The #23 is a fairly neutral solid state amp (some say
"dark" but I did not find that to be the case). Thiels
tend toward brightness and require careful amp matching.
They also require lots of power to sound their best. I might
consider a high powered tube amp.
I never could tame brightness or harshness in the system,
which I think was due more to the speakers than the amp.
The #23 is a fairly neutral solid state amp (some say
"dark" but I did not find that to be the case). Thiels
tend toward brightness and require careful amp matching.
They also require lots of power to sound their best. I might
consider a high powered tube amp.