I remember hearing these several times years ago at a shop and was impressed. Almost bought them. I think the dealer mainly used tubes (EAR and Aronov, I think), although he also used some ss amps (EC and a class A SS amp, I believe). I think the tweater could be a little bright with the wrong SS amp, but they have good resolution, so I wouldn't use a very warm sounding tube amp either. Some of the ASL tube amps may be a good match, or a Sudgen integrated. Maybe even a Pass alpha, or an Aronov if you can find one used. Good luck.