I am currently using a sit 2 from Nelson. It's very quiet and very dynamic. I use a tvr for pre amplification. The First few days have been very impressive. It will drive even my 89db bright stars, but shines with the triangles. For jazz I use omega 3s or the Abby's. it has a huge sound stage with well controlled bass and sweet midrange. It seems to work it all sorts of types of music so far.
This is my third amp from Nelson. I have the f5, powerful but slightly dry, the F3 smooth dynamic perfect for jazz with single source or efficient multi driver speakers.
I recommend a trial from Reno Hi Fi, talk to Mark.