Experience with Simaudio Moon North amps

Zuesman that is great! Happy you love the 861 so much. I’m also smiling b/c that implies, by your calculations, the 761 beats amps in the 0.75 x 60,000 = 45,000 range ( it’s about 75% as good as the 861). I have never heard a 45k amp, much less had the opportunity to directly compare such amps in my specific system, so I can’t comment, but I can say the 761 is phenomenal across the board and has beautiful synergy with ATC. I also found that the 761 responds well with a DPS 4.1 power cable. Happy tunes!

Since we are talking about the synergy between the preamp and the moon amp, I'll share my experience. I heard the moon audio 761 paired with macintosh's flagship preamp C12000. 

It sounded incredible. It was open, rich, fluid like. It really was a surreal experience. It was so good. I bought the C12000 preamp and I'm gearing up to get the 861. 

So, the Moon 400M's are not in the same ballpark then? A step down perhaps.

I ran the 761 for a month and returned it.  IMHO, it had an upper mid-range frequency emphasis that made it lively but much less warmer than the 760A.  I preferred the 760A sound paired with a Mola Mola preamp. The presence of the 761 makes sound stand out and feel more real or "present" in the mix but definitely colors the overall sound, and not in a good way IMHO.  I'd recommend an old 760A over the 761.

@ackerdo finding synergy is the battle! I had the 760A for several months and really liked that amp. It’s a tad darker and not as transparent/ revealing as the 761, which totally gets out of the way of whatever it is fed. Speakers matter too as do cables, and so all those + or - get us to the final sound. I would not say the 761 colors anything, perhaps that it’s a wide open window and sometimes we don’t like what we see. I’m coming up on a year with my 761 and it keeps surprising me with its potential. Receptive to power cord upgrades over stock. I have a Nordost Tyr2 on it and it’s a good synergy. DPS 4.1 was also very good. I found with my 860av2 and 760A,  those amps really responded well with Audience power cords. Awesome the 760A punches your ticket, that’s an excellent amp!