I agree to an extent but with SS, which I'm familiar with, a house sound is there to one degree or another no matter which speaker is used with it. For example MF equipment always sounds the same to me. Other examples are Krell, ML, Ayre, Naim, Theta. Now within certain brands or brands that have a broad product offering I can hear differences. Probably the best example of this is McIntosh. Their low-end integrateds sound vastly different from their high-end separates. One other caveat - the speakers can't be different technologies, for lack of a better word. For example I wouldn't compare horns to regular dome drivers to electrostatics but as a generalization I can hear the brand sound pretty clearly. The difference the speakers make vis-a-vis the brand of amp is in degree not in kind.
regards, David