high ralph:
i complement you for an excellent question ?
the answer is somewhat obvious. since the quad is as transparent as it gets within its frequency response, it has no sonic artifacts and is low in distortion. by feeding a signal which is subtractively colored, i can voice the frequency response and presentation, without the usual comprimises of box speakers. i achieve the frequency response i want, create euphonic coloration and do so without grain, box colorations and other annoyances of other speakers.
it is much easier to color a clear window than it is to color a tinted and dirty window.
by the way, regarding the dehavilland amps, i heard the predessor. unless the new one sounds very tubey in the classic sense, i doubt i would like it.