Tube amp with Vienna Acoustics Beethovens?

I'm not sure what aspect of your sound you are expecting to improve with a tube amp. Tube amps do sound different from each other tonally speaking, so I would assume you are looking for liquidity and bloom, not more warmth. Personally I would be looking at some of the push pull 80wt (+/-) amps using. Look at getting one from a well known manufacturer so if you are not happy it will be easiy to resell and not loose a lot. Think CJ, ARC, VTL, etc. The CJ ll is a nice place to start. Easy to operate and easy to resell, and sounds quite nice and has adequate power. I see them selling for well under $2000.

FWIW I have some 4ohm speakers which I have driven with 4 different tube amps, a 35wt integrated, a 60wt triode, an 80wt pentode and a 160wt pentode. The speakers have 2 woofers, 2 midranges, and a tweeter. They are ported. They have an efficiency spec of 92db. The larger amps drive these speakers with ease at volume levels that can overload the room at 4 or 8 ohms. The smaller amp has the same capacity, volume wise, but for some reason do not sound as smooth in the mids/highs off the 4 ohm tap, which you would think the speakers should be connected, although the bass is just fine. Off the 8 ohm tap they are much smoother but the bass is just a tad soft, a little of the impact gone, but very little.

The point of all this is that some extra power can go a long way, that is the larger amps can drive the speakers better throughout the frequency range even though none of them is really max'ed out power wise. The 4 ohm speakers sound fine on the larger amps on the 8 ohm taps - as with the smaller amp the highs seem smoother. I suspect that the larger ones just have better transformers and can drive the woofers better even at a higher impedence.

Hope this helps some in your decision. FWIW 100 watts of tube power is a lot of power!