I've always liked the Luxman/Sonus Faber combo. Your 509Z is actually the first one that comes to mind since in my opinion it is a little more punchy or full bodied than some of the others. Especially the tube designs. As someone said above I think you might have a hard time beating what you already have.
Best amp for Sonus Faber
Which integrated amp do you believe is the best match for Sonus Faber Olympica Nova (and why)?
Currently using Luxman 509Z - and have just bought Olympica Nova III.
I’ve heard a lot of different views: Hegel, Accuphase, McIntosh etc
Keen to hear thoughts and experiences - and any which a big mismatches too!