Casimim
I have Tympani IVa's and I am using a Mark Levinson 23.5 with good results.
This was recommended "off the record" by a source at the factory who said it was the best amp he ever heard with Tympanis.
True they can handle just about as much power as you want to throw at them, and some Magnepan gurus suggest that biamping is really the best way to go.
Good luck and have fun.