I agree with Atmasphere--most tube amps, both single-ended or pushpull, benefit from driver tubes with more oomph than the 12AX7 or 12AU7, which often means a 6SN7.
By the way, Atmasphere is being quite diplomatic by not mentioning the type of amp he manufactures and sells, which are output transformerless (OTL) amps. If you think your full-range driver system sounds incredibly alive and vibrant with your typical single-ended triode amp, wait till you hear it with a good OTL amp.