Extremas really suck power and you're better off going solid-state.
That said, the big VAC monoblocks (Renaissance 140's or 220 watt/channel KT-88 amps) will drive them -- they have excellent output transformers and power supplies -- but if you really want to use a tube amp with a speaker like that, the CAT amps are the best choice (because Ken Stevens uses far and away the best output transformers). I own Renaissance 140's.
I would go with something Rcprince alludes to, namely, a Class A-biased solid-state amp, like the Lamm and (especially) the Gryphon monoblocks, with Extremas.
There are previous threads on the topic of powering Extremas here on A-Gon and at Audio Asylum.
That said, the big VAC monoblocks (Renaissance 140's or 220 watt/channel KT-88 amps) will drive them -- they have excellent output transformers and power supplies -- but if you really want to use a tube amp with a speaker like that, the CAT amps are the best choice (because Ken Stevens uses far and away the best output transformers). I own Renaissance 140's.
I would go with something Rcprince alludes to, namely, a Class A-biased solid-state amp, like the Lamm and (especially) the Gryphon monoblocks, with Extremas.
There are previous threads on the topic of powering Extremas here on A-Gon and at Audio Asylum.