Would a stereo Sim Audio Moon 861 amp be as powerful as 2 McIntosh 611 monoblock amps?

You should consider the 761 amp for your speakers over the 861 because your power requirements are low (save your money). I heard the 761 with the Moon 791 preamp / DAC and Paradigm Persona 9H speakers. This is a combo I would never pair together but it was an interesting listen.

I would use the much cheaper (and preferred) Benchmark LA4 preamp with the 761. The Holo Audio Serene preamp over the 791 if you want a bit of warmth.  I have not heard the Raven Revelation tube preamp, but I have been discussing the Raven with the Benchmark AHB2 amps with a fellow A'goner. This person finally got the AHB2 monos and loves the combo.

I mention this because my impression of the Moon 761 was that it was the next (and better) iteration of the AHB2 amp. It sounds a lot like the AHB2 but with a bit more body to it. The Raven and 761 should be a great combo based on the Raven and AHB2 pairing. More like the Serene preamp.

Having a separate preamp allows you to get a great DAC such as the new Schitt Byggi coming out in Aug 2025 for $3500. My Schitt Yggi+ OG DAC + Benchmark HPA4 preamp are an easy pick over the Moon 791. 

@stuartk I know Jason Stoddard is a salesman, but I do believe he backs up his bravado. I say this as someone who bought his new Wotan amp based on his comments and I ended up loving the amp, especially for $2k. 

I initially thought Schitt was a joke of a company based on the name and marketing. However, something made me buy the Yggi+ LIM DAC and I loved it with my bright RAAL SR1a earphones. I have spent a ton of money getting that phone to sound great. At that time the LIM was the best DAC I got to pair with the SR1a.

Today the SR1a is much easier to get sounding great. The LIM was then used on my 2-channel gear, the Yamaha NS5000 speaker specifically. It was not good at all. I then converted my LIM to the MIB for $900 even though I knew another big Schitt Yggi+ DAC upgrade was coming. The MIB is closer to the cleaner OG sound, but it is still not as great as the OG. I feel I wasted that $900 on the conversion. I am on the queue to upgrade to the Byggi for $1500. 

I am doing this because the LIM and MIB left me wanting something better. Unfortunately, my curiosity made me do the $900 conversion instead of buying another Yggi+ OG that was on the used market for $2000. If I had gotten that I would not upgrade to the Byggi. I would then have had 2 Yggi+ OG's.

Jason was bragging on Head-fi that the Byggi is the best ever DAC they have made, and it is much better than the LIM and MIB. I figure they are trying to recapture the magic of the OG. I have nothing to lose since the MIB is not an end game DAC for me.

BTW - I love the MOON 761. That is one great amp.