Tube amplifier to power Sonus Faber speakers?

Here is the simulated load graph that the Ref75 was tested with (1st link) as you can see compared to the flatness of the FR graph (2nd link)black trace, That this amp is relatively flat but is already dipping at 200hz.
But the simulated load at the 200hz is not that heavy and would be far lighter than the SF EPDR of 1.7ohms in the bass.
So even the mighty Ref75 might not fair too well in the bass with the SF speakers..

http://www.stereophile.com/content/real-life-measurements-page-2

http://www.stereophile.com/content/audio-research-reference-75-power-amplifier-measurements

Cheers George

Here's my suggestion and for a LOT less money than the ARC Ref 75....
see if you can source an ARC D70 Mk1, or better still, a Mk2. With my SF's, the D70 Mk2 makes beautiful music. If you think you may need more power ( which I would doubt), then look at a D115 or better a pair of M100's. These older W Z Johnson designs are still IMHO very competitive with some of the best tube gear around. Plus, with the older designs, one isn't stuck with having to run a balanced only preamp up-line.

I used to have B&W 805D2 with Mcintosh MC275 tube power and worked beautifully. I change the speaker to Sonus Faber Olympica II and still produce an great sound. Although I think I lost a little of high frequency because of diamond tweeter. But still its a great combo.