It is why I never part with the old equipment before a long time with the new one just bought. I always like to re-listen with the old equipment after some time with the new one. The major problem of this way of buying is that my storage room is now too full!It takes a long time to weigh emotion, content and true quality before one can decide if the change is an improvement we can live with and enjoy over the long haul.
However there was a recent acquisition that really did not need to go through the re-listening phase - the Audio Research Anniversary preamplifier. It was better than the Ref5 in every aspect! Curiously the gap between the MB750s and other amplifiers playing in the Sound Lab´s enlarged with this preamplifier - they really match!