I have a pair of VAC Phi 70s and I like the sound so much I wouldn't touch the factory tube configuration. Then again, I'm biamping a pair of B&W Nautilus 801s using the Phi 70s for the uppers/midrange and a Krell integrated for the woofer. I'm using the 8 ohm taps out of the Phis (I tried the 4 ohm given the complex impedance curve of the 801s but the sound was ever so slightly polite and recessed compared to the other, so I switched back). This is a pretty nice setup, with a very open and airy top end (compared to solid state) that I don't find at all "romantic" or "lush". Maybe its not trying to use the tubes for the low end? I don't know.
