Experience with Simaudio Moon 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..   

@kerrybh sorry for delayed response.

Regarding my conclusion: it’s not a hard conclusion, more like a soft one, that is based on personal experience, accounts of other audio nuts, and guided intuition. The intuition part stems from the true dual mono design of the 761 and 861 amps; They pretty much are mono blocks in philosophy: they only share a chassis and a power input IEC socket. Each channel has its own well specified power transformer and related power supply components. The crosstalk (aka channel bleed) is ridiculously low, better than -115 dB on either amp. I don’t think it would be THAT aspect of such a design that manifests less capability to achieving a satisfying soundstage vs true mono blocks. I think the advantage of individual mono blocks is that of power. Dedicated monoblocks typically have more power reserves and depending on the speaker, may yield more separation as volume increases.

In a dual mono config like the 761 or 861 I think this gap would be pretty small, but in the realm of extreme audio performance, if that is the goal, then separate chassis and power cords (maybe even wall sockets because if they are plugged into the same socket then they are effectively strapped together at the same AC line feeder circuit) may be the way to go to audio nirvana. At some point the tradeoff just might not be worth it. Totally a personal decision.

There is another dimension to consider with stereo amps that can be switched to operate in ’monoblock’ mode: TONE and COHERENCE. I used to have a Luxman M-900U (had it many times actually, lol) and this was a pretty beefy stereo amp. It could be switched to operate in mono mode, and with another M-900 one could get massive power. I personally did not ever hear a setup with dual mono M-900’s but I have heard (from dealers and forum reviews) that the sweetness and coherence of the single stereo M900 is somewhat traded off for more balls and punch when in the mono config. In other words, the character of the amplifier changed. This is not to say that all mono amps present less coherence and potential "sweetness" it’s just something to think about, and it’s ultimately a function of the amplifier topology and the rest of the system. Make sure you listen to both options before doubling down on another chassis.
Happy Hunting

Thanks. All of that makes sense. I'm in the beginning stages of thinking about this, but like simaudio. Was thinking about dual 761s or a single 861. The 861 should certainly have more than enough power and I rarely listen at level above 85 dbl. Does the 861 incorporate improvements over the 761 other than having more power?

Thoughts on any of this are appreciated.

Simaudio hit the ball out of the park with the 791/761 combo. If you are in the beginning stages you might want to consider going with the naturally synergistic 791 or 891 with whatever amp you choose. I think the 761 and 861 are very similar, on paper (reading Simaudio Website) albeit more power on 861. If it were me I’d go with the larger stereo amp, the 861 and the 791 (or if funds permit the 891), strap that to your Sonus Faber and call it a day!  Two beautiful chassis’s and reference level  performance.