I'm currently using an EL34 amp (Radford STA100) with my 91db 12in HPDs, while my KT88 STA100 is restored. It certainly outperforms the Leak Stereo 20 I recently sold (for all its charms - I do like that amp). But I'm firmly of the view that all Tannoys love a bit of valve push pull welly and there's no harm in putting 50 or 60w to the job as opposed to the 35w you typically get from EL34s.