I’m with ct0517 on this one (and other ones. We both love and own old Quads). The speaker/room relationship is for me the most important consideration in a system, and the place to start. This is a matter of some disagreement, but there is far more difference in sound between speakers than amps in ways most important to me: truth of timbre, lack of vowel coloration, etc.
If a, say, planar speaker is chosen, different ones work better with certain kinds of amplifiers than with others. You’re not going to put a Sanders Magtech amp on the old Quad, but an Atma-Sphere S-30 or Music Reference RM-10 would be perfect. And neither of those is right for a pair of Maggies, but a Magtech is.