As an addendum to my previous comments, the Ref 5 now has a little over 200 hours on it and has improved markedly in terms of perceived frequency extension, micro-dynamics and its ability to capture the natural weight and dimension of instruments in space.
Third order harmonic information lingers even longer, further outlining the recorded venue and space around instruments but not in the traditional "tubey" way. It continues to strike me that a lot of the gains over the Ref 3 relate to background silence, quicker transient articulation and a rock solid foundation in the lower octaves, which opened up and clarified huge amounts of lower midrange information I was missing before.
The uppermost octaves nay or may not be measurably more extended, but unquestionably there is far more diversity in terms of tone and textural contrast apparent, such as the multicolor sheen from cymbals or the resonance from stringed instruments. The solid state like character that I referred to in a prior post has abated but what remains is still far more clean, defined and direct sounding than the Ref 3, which in contrast reminds me more of the Ref 2 (which I had at home and did not like (too slow and tubey). In short, the Ref 3 by comparison has noticeable mid-bass overhang and sounds noticeably slower, lacking immediacy, coherence and upper frequency transparency.
Put in perspective, the differences are obvious and well worth the increase in retail price (to me), but impressions may vary from system to system depending on context. In my experience pre-amps are more sensitive to system differences and contexts except speakers, than most other components including amps and front ends, so all this is FWIW. Again, the difference was more dramatic than going from the CD-7 to the CD-8.
