Should I get the Moon 891 streamer/dac/preamp for my Moon 861 amp? Or separates?

I agree that a lot depends on your overall system and preferences.

I have the Moon 891 and a pair of 761 amps in bi-amp mode.  I have high end interconnects and custom designed speaker wires.  The speakers are Sonus Faber Serafino.  The room is 17' by 16' with 8.5 foot ceiling with acoustic tiles and wall to wall carpeting.  I also have carefully controlled power.

The Moon system is terrific.  Reasonably but not overly analytical and not mushy.  I listen to mostly classical music mostly streaming on Qobuz.  This works well.

A lot depends on the speakers.  Sonus Faber goes great with Simaudio Moon.  Sonus Faber are also on the warm side compared to say Magico.  

So, as noted by others, a lot depends on your overall system and preferences. but chances are the 891 will work extremely well.  One final point.  Simaudio is a terrific, reliable company.  They have been entirely supportive of me as I developed the system.

@dman777 

It’s almost always better to go with separate components.  Think of a Swiss army knife.  It can do twenty things, but does it do any of them well? Another reason for me to get separates, is I want a different sound?  I can switch the DAC or switch to a tube preamp. 

@dman777 that’s right. You should work with a dealer that will let you demo the DAC at home in your system. 

While I agree you shouldn’t buy blind, I can tell you that I’ve heard the North 861/891 combination and it’s very, very good. Can you do better? Sure. But, the $25k spend for a device that includes a quality DAC, streamer, and preamp, while eliminating the need for several expensive cables, is not excessive but a strong value. Importantly, to borrow an old phrase (that’s not quite so true any more) from Apple - “it just works”.

I think the weakest part of the North system is their streaming function, but it’s still quite good and the software seems stable. 

Honestly, I have two systems - both of which I’ve managed to make more complicated than necessary. If I were to do it over - for at least one of those systems, I would pair their 800 series preamp/DAC with the 761 amp which I own already. I’d be happy to- and essentially done. And have spent a LOT less time and money getting there.

My $.03 (inflation)

@audphile1  I wish that was the case, it would make life so much easier... I have heard of those. There are none where I live. 

@mgrif104 Thanks... that is the impression I have gotten so far from a dealer that I spoke to. He said that since the 891 is more recent with tech. it sounds as good as separates that would cost more money. But I have android and I am a little worried about the app. Also being locked in to just one app I am also worried about for that price level. With separates, I was thinking if the app was horrible I could at least switch streamers?