Ypsilon Electronics

I have heard them twice at show conditions. Each time the sound was at least very good. They are uber expensive though ~ $70k.

I agree with Elberoth2,

they sound very refined and are sonically balanced towards the warm sweet side, look good, but are extremely expensive. I have not heard them in my own set up, but I have heard them many times at shows over the years.

I am very privelidged to say that I have heard the Ypsilon SET 100 mono amps driving Sound Lab A1 speakers in Leonard Tam's demonstration system at the Revelation Room in Singapore.
The grip and dynamics were amazing, like nothing that I have heard or fealt before, much more so than my Sound Lab U1PX's being driven by ARC 610T's.
Maybe one day I may trade my ARC amps for these superbly made hybrids.
They also make - but not heard - a c.d. & dac, line stage, and have just produced their first phono stage.
Worth seeking out.