Well, I'm sitting here listening to my vintage Quad.......405-2. Having owned the Quad 909 before, I much prefer the 405-2. It has the midrange, but it also has dynamic power and smooth upper frequencies, far from rolled off. The bass is nowhere near as deep as my class D amp but it has an unforced, realistic quality. It's a finer quality. As for the soundstage, there is a cohesion of presentation that doesn't have the piano left and right hands separate, nor is the voice forward of the band, but it can still create those startling stereo experiences of sound coming from outside the room.
Quad 909 back in the day had a reputation for the best mids running up to $5000. I've used it in the past and I would definitely say that the mids were the highlight on that amp. It wasn't overly coloured, a hint of warmth, but it had a purity and sweetness to its mids. Unfortunately, mostly everything else was okay at best, kind of rolled off at both ends and congested stage-wise.