I got to hear a Purifi 1ET400A based amp today in a very good system.
It is almost really good but let down by having quite poor imaging -especially poor centre fill and image depth so it sounds very 2D .I was really surprised it sounded like that.The Accuphase amplifier in the same system had fantastic image depth /projection and height.We tried with and without active preamps and that did not make any difference.
Perhaps I need to recalibrate my expectations to fit in with modern amplifier technology ?I always used to believe that the whole point of stereo reproduction was imaging.
That's interesting. When I first put my Purifi amp in my system, I noticed excellent soundstage depth in particular. It was a subjective, sighted comparison with my prior amp, but with that disclaimer, I will say that improved soundstage depth was one of the three main improvements I noticed (or thought I noticed, anyway), along with less distortion and lower (or in the case of the Purifi I should say basically non-existent) self-noise.
My first impulse would be to suggest that a higher-distortion Class AB amp might add some detectable 2nd harmonics, which can create a false sense of ambience and "air," which in turn can influence the perception of soundstage. However, my understanding is that Accuphase amps have very low distortion, so I doubt that would be the cause.
At any rate, you heard what you heard - but you'd be wise not to attribute your single experience to some objective quality of Purifi amps.