Your Quad is going on thirty years old. In it's day, it was a very good amp. Nowdays, it will have a hard time sounding as "musical" in comparison a lot of "mid-fi" gear. No doubt- you are hearing a lot of definition that you've been missing. There are a bunch of people that refuse to admit(or face the fact) that there have been a number of improvements with regard to the electronic components(passive and active)used in the manufacture of audio gear since the 80's. Count yourself blessed that you can hear the differences.