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

You won't notice on 91dB sensitivity speakers. You’ll be blown across the room before those amps hit 20% of their output power.

For your 85 dB target level it won’t matter; either amp will be way way more than ample. It won’t matter till you’re pushing at least mid-90’s or above, continuous. Maybe not even then. 300W is a LOT of power. Most speakers are not rated to sustain that. 

You’ll almost certainly prefer the sound of one amp or another, but it won’t be due to lack of power capabilities. 

I believe yes based on my experience with both brands. 
 

• I compared McIntosh MC-462 (450 watts/channel) versus Moon 330A (125 watts/channel) with Sonus faber Olympica Nova III and the Moon was more dynamic 
• I bought 2 Moon M400 - mono version of the 330A rated at 400 watts.  I replaced those amps with Moon’s 860A v2. The amp was a significant improvement in every way. The amp is rated at 225 watts/channel 
• I had a McIntosh MC-302 (300 watts/channel) prior to switching to Moon. 

I tend to listen loud commonly 85 dbs though I strive to keep it under 100. I used to be an artillery guy so I am used to loud things. I’ve never experienced my 860 getting warm.  
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I enjoyed my McIntosh but the ‘watts’ aren’t the same as Moons. I don’t think the 611s would keep up with the Moon 861.

@mulveling +1

Mike

@overthemoon oh wow thank you for sharing. Can you please tell me what preamp you are using with the moon 860 amp?

Moon 791 - I initially used a 390. 
 

You may want to consider the 761 amp as well. 

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. 

@yyzsantabarbara 

Having a separate preamp allows you to get a great DAC such as the new Schitt Byggi coming out in Aug 2025 for $3500

Schiit loves to brag about parts and technical data. I'm not an engineer so such info tells me little about sound. Just wondering whether you have any expectation of how, sonically, the Byggi will constitute an improvement, based upon your familiarity with various past and current iterations of Yggy.

@overthemoon  I was at the audio store and I heard the moon 761 with a Macintosh C12,000 preamp. It sounded really good. I didn't get a chance to hear it paired with the moon preamp. Would it be crazy to pair the 861 amp with the Macintosh c12000 preamp instead? I was wondering if it was the tubes  that complemented that sound really good

@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.

SPL wise, surely either amplifier will get you to 85 dB SPL for most listening positions in most rooms.

I do not guess which Dynaudio model you are after, but I see the Confidence 50s are specified as 4 Ohm speakers, with drops to 2.7 Ohms. Mc 611s, with 2, 4, and 8 Ohm outputs, would offer you options to explore how the different taps, with their graded maximum current capacities, match the speakers.

YMMV, but I'd prefer to have the flexibility. Experiment.

As others have said, either will deliver far more power than you will need. I'm familiar with those amps and they will likely have very different sounds. The Sim will be very detailed, transparent and analytical-although I enjoy the Sim sound, too dry for some tastes. The Mac will sound like a Mac, softer, less detail than the Sim.

If you are really concerned about power, you might consider the Michi S5. More power than you would ever need and built to last. I just replaced one in my system and tried the Sim North 761 when I was looking. In my system, to my ears-we all hear differently-the Michi had a better sound-the same level of detail, but a bit more natural. At about half the price.

@dman777 I don’t think anything is crazy. Many folks like to use tube preamps. I had the McIntosh C2600 and thought it was wonderful. 

I was asking in this thread because I own a Yamaha AS 3200.  I played at 70% volume to get about 70 DB. After 70% it starts losing its sound quality really bad and sounds thin. I want to make sure my next smp has plenty of headroom

@yyzsantabarbara 

Thanks for your response. A disappointing audition of the Mojo Mystique XSE has challenged my previous conviction that a warm sounding  DAC would be the right fit for me. In the past, I’ve noted your enthusiasm for Schiit DACs so I thought I’d ask you about the Byggi. I will research sound signature of the OG.

I was asking in this thread because I own a Yamaha AS 3200.  I played at 70% volume to get about 70 DB. After 70% it starts losing its sound quality really bad and sounds thin. I want to make sure my next smp has plenty of headroom

That really indicates something else is wrong. Not raw power. Your speakers should be pulling a fraction of a Watt to produce SPL's under 80 dB.

Volume controls are never linear, so 70% on the dial (or 70% of its max numeric value if digital volume) would be much less than 70% of full power. That said, if you have to go 70% to hit 70dB, then your system could be lacking the necessary gain to tap the amps' power reserves. Many modern systems are on the other side, having more gain than they need. A poorly matched cartidge & phono stage is the most likely culrprit for a gain-starved system.

Or you could be fine on gain, and you just don't like the Yamaha amp (or something is wrong with it), or the speakers, or the match of amp to speakers. If you're at volume 70 and the full range is 1-100, and each digit represents 1dB, then 70 is actually 30dB down from "full gain", which means 1/1000th (or 0.001 = 0.1%). 

I’m using a pair of Sopra 2 speakers.  When I purchased them I was using a Simaudio 700i amp. It sounded great, smooth and detailed.  I switched to a McIntosh MA9500 that had a lot more power. 300wpc I believe. It has a totally different sound that I liked better. I usually listen at 85db avg. and the Mac rarely hits 30watts. At those levels the 700i sounded a bit strained. With these speakers I think the Mac is a better match, especially in the Bass. 

I agree with @mulveling , sounds more like a gain issue than a power issue. Many times the two are conflated.