The A. Excellence guys were the ones who declared the 390 and 590 warmer than the rest of the line and the 390 the warmest. I don't claim to know which model would best suit the speakers in question or the OP's tastes in terms of tonal presentation. I only pointed this out in the context of comparing one Hegel vs. another and because, as far as I was aware, this distinction hadn't yet been mentioned. If there were no sonic differences between the 290, 390 and 590, then I'd agree the choice could be boiled down to power requirements alone or "need", as you put it.