Experience with Simaudio Moon North amps

I have had the 761 stereo amp for several weeks now; I’m pairing it with the 791. It’s powering Opera Callas Diva speakers (also handmade in Italy). I can’t say enough about this amp. I love it. I don’t see how you could go wrong with the partnering equipment you have listed. Octave preamp output impedance is low enough to not cause any problems with either Moon North amp. The clarity, dynamics, and reference level performance of the 761 or 891 will let your source components shine and very likely bring out the very best from Sonus Faber speakers. You may have to dial things in to your specific tastes with cables, but again I think you are on a good path. For what it’s worth, a single 761 in stereo mode packs a punch. It’s rated to 400 wpc continuous into 4 ohms. Assuming you have a massive room and like to play at party levels for wanting to consider mono blocks.
Happy Hunting!

Thanks to you both. I used a moon 390 for several years and have a moon phono stage. I’ve been very pleased with simaudio products But have not had a chance to hear anything from the new north collection.

The primary reason I would consider mono is to maybe get a little improvement in the soundstage, but the amp certainly has plenty of power. Happy to hear the positive review.

@kerrybh My two cents: If your room is optimized acoustically, meaning optimal speaker / listening chair placement and (possibly) necessary acoustic treatment, like absorbers, diffusors, and bass traps you might benefit from the mono-block topology for theoretically increased soundstage/image. If you consider the crosstalk specs of the 761 or 861 stereo amps, both better than -115 dB, and superlative SNR figures, on paper at least, it begs the question of HOW can mono-blocks render different soundstage. The conventional 'wisdom' is that mono config might yield better soundstage but I doubt it would be night and day, and to unlock the full potential, all the other acoustic parameters should be addressed. Maybe it comes down to the extra current and power on tap, and that monos each work less, which possibly manifests a different stage. These days i'm aiming for simpler setups, hence a stereo amp. I am sure though either way you would be SUPER happy with the North Amps. 

Thank you for that perspective. My room has been professionally treated, and I think it is set up reasonably well, although there are some factors that are hard to address.
I’ve never owned monoblocks so I don’t have firsthand knowledge, but have heard that monos would make a significant difference in soundstage which is an important factor for me. If the difference would not be significant, I would prefer the simplicity of a stereo amp  I would be interested in how you reach your conclusion if you don’t mind sharing. Again, thanks for your perspective.

@kerrybh I used to have a 390 - I think it's a wonderful unit.  I was shocked at the difference in sound when I swapped two M400s with for a 860A v2.  It's an upgrade in every way even though I went dual amps to a stereo amp.

I believe the 761 has similar characteristics with the 761 - I bet you will see a significant improvement. And just like the 860A v2, the 761 is a dual mono amp..