In which ways was the Impera better than the Ref 5? How would you describe the character of the Impera?
Well, I will start by answering your last question. The Impera has a very linear response, from the lowest octave to the highest. It will not bloat anything but
without making anything sound asceptic neither. It really builds upon what is associated as the upside of tubes (soundstage, natural timbre, harmonic extension, micro-dynamics) together with speed, heft, very good resolution and excellent dynamics. Yes, I am biased by saying this ... because I based my purchase decision on those criteria...
Major improvments of the Impera vis-à-vis the AR Ref5SE: resolution at the extremes as the low end left me wanting for example by the AR as it lacks heft and being able to distinguish the different bass lines. In other words, I found the AR to have bottom yes, but much less defined.
At the other end of the spectrum, the Impera goes on and on without sounding shrill or painful. The AR doesn't, it seems like cut off earlier or it can't handle the dynamic contrasts and reach needed to capture the full musical production.
The AR, in comparison to the Impera, is less linear and has an emphasis on the midrange.
Finally, the Impera (as other Aries Cerat) has a very low noise floor making you being able to connect much better with the performers.
The outcome of the comparison with the Pass XP20 was a bit different of course. The Pass being notably 'flatter' in sound image, less extended at the extremes, less harmonics richness, less capability to connect to the performance.
Caveat: only classical music used for evaluation.
(you don't have to do this, but if you do, it will answer many questions regarding preamps). For me Koda is out since it does not have a remote. Difference in these preamps is too small to warrant not having a remote. Ypsilon is single ended only, though it sells additional transformers for XLR outs.
