Which Amplifier for Sonus Faber Olympica 3 Speaker

George - the older SF were, as you say, notoriously hard to drive due to impedence and phase angle issues. However, the newer designs are typically much less taxing. The Futura graphs look more like the old designs, which may simply mean that they kept some of the old design. Stereophile did review the Venere 2.5 and found it much easier to drive than older, higher end models. That is not surprising since it is meant to be a more entry level offering. I believe part of the design criteria for the Cremona M was to make it easier to drive than the original Cremona. I believe they probably carried over that philosophy to the Olympica design. Since Stereophile has not measured the Olympica 3 it is hard to know how easy or hard it is to drive. But my guess is that it will much easier to drive than the Cremona or Amati Futura that you reference.

Venere 2.5 Measurements

My local SF dealer demos the speakers with both Audio Research (reference series) and Rowland SS amps with excellent results.

DTC this may be true for the cheaper SF's but doing some more searches reveals the opposite, that the Olypia 3 are really a 3ohm design and has 2.6ohm dip at 103hz.
And at 81hz it has an EPDR of just 1.7ohm load to the amp.

Sorry but this model is a b***h to drive and needs big amp/s with good current delivery that can nearly double the wattage all the way to 2ohms, "if" you want to hear the best out of these speakers. .

Just look at the lab report from Miller Audio Research Labs in the link
http://www.absolutesounds.com/pdf/main/press/05:14_SF_OlympicaII_HIFINEWS.pdf

Cheers George

For what it is worth, I enjoy my Concerto Grand Piano speakers paired with an Anthem 225 Integrated.

May not be in the same league with other gear mentioned, just an opinion. The GP's have sounded lackluster with some of my gear /cable combos.

The Anthem brought out the best as did Morrow SP4 cable.

My apologies if my comments were off topic.

Kind regards

George - the review is useful. Thanks. What has typically made SF hard to drive is not just the impedance but also the phase angle. The Miller report does comment that the phase angle is well controlled, so the speaker may not be as hard to drive as the impedance along would indicate. This would be consistent with the fact that the Cremona M is much easier to drive than the Cremona. And the Olympica is the follow on to the Cremona M.

I agree that I would be careful with a lower power amp, but the Miller comments seem to indicate that a monster amp may not be needed to drive the speakers.

Unfortunately, I do not know enough about the amps the OP is considering. The Hegel 300 is 250 watts at 8 ohm and 430 at 4 ohm. Does not double down but it may well have high enough current to drive the Olympica. I would not dismiss it, especially given the Miller comments.