Inna,
The bass quality of an amplifier is so tied to the speaker that you really have to discuss them in tandem as this link is that strongly intertwined. In the example I cited the Rockport Altair is 4 ohms nominal load and drops to roughly 2 ohms in the bass region. I will concede the Krell FPB has excellent control of the Altair woofer and has superior weight, impact and scale.
However the Absolare Passion is quite accomplished in the bass (by no means is it shabby) with very good texture, articulation and convincing natural bloom and air. So IMO it's a matter of "good" vs exceptionally executed bass performance. I could and would easily live with the Absolare Passion-Altair bass,why? For me it's good enough bass and in virtually every other sonic parameter a sublime amplifier in areas that matter most for my satisfaction.
Choices and compromises we all must decide individually. If I were to own the Absolare I'd just find a speaker with a less demanding load and thus more compatible with this brilliant amplifier. When I heard the Ypsilon amplifier it was driving Tidal speakers and there were no bass issues that I detected. Again, appropriate speaker match.
Charles,
