I really would be interested in a comparison of the 75SE, against a 75 with just the added KT150's and no caps changes etc. I suspect 90% of the difference is the tubes and the other upgrades are an expensive irrelevance, but it would be nice to be sure.
Audio Research 75 SE
I just heard there is an Audio Research Ref 5 SE and they are offering the update to Ref 75 owners. Not only includes the 150 tube but also some circuit changes to better accommodate the new tube. Audio Research states this is a dramatic improvement as much so as from Ref 5 to the Ref 5SE.. Anybody heard it.