You are going to get a lot of suggestions, and since this is Audiogon, most of them bad.
Only a tiny handful of tube amps have output transformers and power supplies of the quality necessary to drive speakers that drop below 3 Ohms in the bass, and they are all extremely expensive. If I were running speakers that present a tough load and just had to do a tube amp, I would look only at the CAT amplifiers, which have the best output transformers I am aware of. They are a real hotrod design, however, and require soldering when tubes fail due to resistors frying upon tube meltdown (which happens frequently because it is a hotrod design). Other options would be the Air Tight Reference and VAC's Renaissance 140's. My guess is that the VTL Siegfried would also work. Generally, you have to be most careful in choosing a high-powered tube amp, as almost all of the well known ones are not as capable of driving low impedance speakers as their ratings would suggest (I also find that high powered tube amps as a rule do not sound very good).
All of that said, I would forgo a tube amp entirely with that speaker in favor of a darTZeel, which will give you better overall sound barring some bizarre synergy issue with the rest of your equipment (I have no reason to think that would occur).
Only a tiny handful of tube amps have output transformers and power supplies of the quality necessary to drive speakers that drop below 3 Ohms in the bass, and they are all extremely expensive. If I were running speakers that present a tough load and just had to do a tube amp, I would look only at the CAT amplifiers, which have the best output transformers I am aware of. They are a real hotrod design, however, and require soldering when tubes fail due to resistors frying upon tube meltdown (which happens frequently because it is a hotrod design). Other options would be the Air Tight Reference and VAC's Renaissance 140's. My guess is that the VTL Siegfried would also work. Generally, you have to be most careful in choosing a high-powered tube amp, as almost all of the well known ones are not as capable of driving low impedance speakers as their ratings would suggest (I also find that high powered tube amps as a rule do not sound very good).
All of that said, I would forgo a tube amp entirely with that speaker in favor of a darTZeel, which will give you better overall sound barring some bizarre synergy issue with the rest of your equipment (I have no reason to think that would occur).