I went to a local dealer recently and had the chance to compare the new VSI75 integrated, Reference 75 and reference 110 with KT120 valves. I was hoping to get away with an integrated instead of the Reference 75, as the former is said to have similar circuitry to the ref 75.
All were played through Wilson Duete speakers. There was a very clear difference in sound quality, with marked improvements at each point.
The VSI 75 was clearly inferior to the others, in detail, soundstage, it was grainy and muddy compared with the others.
Next was the 110 with KT120 valves and much closer to it was the Reference 75, which was a clear though not night and day improvement, over the older, but more expensive model. I have the Ref 75 on order.