Well, MC, I think I didn't choose my words carefully enough. I really just meant that SS amps generally have greater dynamic range which seems to be reflected in their S/N ratio, but I couldn't give you a technical reason that relates it back to their designs. I would venture to guess, however, that it has more to do with design limitations of tube amps rather than trends in design choices.
I think maybe you should hear the DCs with a Plinius in particular, because I don't know what other big amp has been recommended by anyone. I think that most SS whoppers are likely to work poorly with the DCs because these speakers won't draw enough current. Lemme put it this way, if the manufacturers publish measurments of their 200-300 watt amp as having a S/N ratio over 105 dB, it's probably going to be at levels above 30 watts. Who knows what the S/N ratio is below 30 watts, which I think is where the De Capos live even at loud levels. To elaborate, I mean that if you decrease the current (signal) going through a big 200 watt amp from 50 watts to 15 watts, who is to say that the noise output will decrease comensurate? The S/N ratio probably diminishes by "bottoming out" in this case, as opposed to "clipping". Actually, "bottoming out" is the wrong term, because you'll never really hear the sound fall off, you'll just hear poor dynamic performance in the softer parts of the recordings, which translates into the tendancy to want to turn it up (at the risk of reaching their loudness peak, once again, limiting the overall range of the dynamics), or the feeling that the speakers just don't "open up" unless you crank it a bit. This was true of Chris' Acurus DIA-150 - I always thought that he listened too loud with it, and I do find that that amp sounds much better with my Apogees, which are 3 to 6 dB less efficient. It takes a very special amp to perform equally well at low levels as high levels, and to do both, the price usually goes up. That's all just to say that the first 1/2 watt may be the most important for the De Capos, considering how good they can sound with 4 or 8 watts of tube power. With the Plinius and the oversampling Gamut CD-1, I'd say that the dynamics compare favorably with bigger speakers like the Wilson Sophias, JMLabs Mezzo Utopias or big Kharmas like I heard in Montreal with two giant Tenor SS amps in bridged mono (300 watts). The bass isn't there, so there isn't the same "umph" but the dynamics in a small or medium room is fantastic. Let me finish by stating that an amp can never "increase" the dynamic range of a recording. If the output from a recording varies from .1 volt to 1 volt at the CD player, and an amp has a gain of ten, it must put out 1 volt to 10 volts - not 1 volt to 11 volts - that would be distortion. Similarily, speakers can't add dynamics, only relay what's there, and the De Capos, with their minimal cross-overs and light drivers put it all into the air. I don't mean to offend, MC, but I think that if you're finding your De Capos don't deliver the utmost in dynamics from 60Hz up, you might want to revisit your amp's compatibility with it. The De Capos go plenty loud, unlike the Quad ESLs. The Quads really don't play loud, so you must have a quiet room and a well-matched amp in order to enjoy the full gamut of loudness, but then the dynamic range seems great (dispite lacking umph, as you pointed out)
Sorry for going off on a bit of a rant; the issues relating S/N, apparent dynamics and overall power deivery in amps is a bit too complex for me to describe succinctly in a technical fashion, so this big round-about banter is the only way for me to cover all the bases
Anthony
ps. if everyone here was also a photography nut, I'd make a big analogy to the quasi-linear nature of photo reproduction. Image contrast is much the same as audio signal dynamic range, and the fundementals of Ansel Adams' Zone System for black and white printing translate beautifully to the many gain stages in sound amplification.
