One of the things I cannot find out about my power amp is whether it is class a or a.n.other. All I know is that it is EL34 push pull with an output of up to 40 Watts per channel in ultralinear or 20 Watts in triode. I was though listening yesterday to Museum Of Consciousness by Shpongle in ultralinear and it sounded bloody sublime (with the sub). As has already been stated here, my guess is that the modus operandi is largely dictated by the music. Bloody lovely sound, well impressed.