Grimm MU1 Streamer - Really "The Best"?

I've recently become interested in the Grimm MU1.  While reviews of top end players from Innuos, Aurender and Antipodes and others are typically all very positive, the tone of the many pro reviews of the Grimm MU1 go far, far beyond, with some reviews resorting to using superlatives and gushing of positive system transformation and not being able to stop listening to material, etc..  HiFi Advice and Steve Huff (actually calls it "magic") have such reviews.

Given the delay in availability of the Innuos Pulsar which I'm told will be better than my current Zenith Mk3 + PhoenixUSB reclocker, I am interested in replacing my streaming setup with a one-box solution that includes a high-precision clock.  The new streamer will continue to feed my Gryphon Diablo 300's DAC module, which I have no interest in replacing.

I'm actually a fan of Innuos, after they improved the sound of my Zenith with firmware updates and after I added their PhoenixUSB reclocker. I appreciate this commitment to improving sound quality which is why I was so interested in the Pulsar.

The trigger for considering an upgrade is not for improved sound, but rather, to solve some issues I have with too many Audioquest power cords coiled and clumped together. I will get to lose one of them and one of my USB cords with a one-box streamer. I've noticed my sound is very sensitive to positioning of my AC cords and find I often need to re-adjust the PC feeding my amp to get proper sounding vocals at center stage.  One of my subs also seems to be picking up AC noise when the crossover is set above 60Hz. The second trigger is simply system simplification, removing one box.  All that said I don't really have any complaints regarding sound, and the PhoenixUSB reclocker truly did improve the sound of my Zenith.

While the Grimm MU1 has it's 4X upsampling up it's sleeve with reviewers absolutely glowing over this feature and it's extreme ability to separate tones to the left, right, front, and back far better than the rest, I don't see that Grimm has gone to any lengths with regard to power supply management in the way other brands do including Innuos. The MU1's ultra-simplistic interior doesn't bug me, but the lack of transformers and power management makes me wonder....

Are there any updates from folks who have directly compared the MU1 vs similarly classed streamers from the competition?  Did you find it to be as revelatory as the pro reviewers found it? And, how does it compare to other streamers with it's 4X upsampling disabled?  Does it sound like it suffers from it's lack of power management?  I do see that the clock should be very good...




Also… in reading the manual for the MU1, I noticed that they state that you must use the variable volume control, and that they recommend not using a fixed volume level. I am interested in how that does not reduce the quality of the digital signal. Can anyone chime in about that?

@peter_s My Grimm dealer believes that the best way to feed the Grimm is a high-end CD transport. Of course that's not the typical use case and would defeat the goal for many folks.

Can't answer definitively, but I'd analogize it to DAC pairings. I've used the Grimm with budget ($1k range) DACs and the Grimm made them sound like $5-7k DACs...but I still prefer the Grimm with the "best" (for my taste) DAC possible.

Hello everyone, the first thing is to congratulate everyone who has participated, this is one of the best posts I have read in this forum. I also have the Innuos Zenith MK3 + Phoenix USB combo, I use the Esoteric K01XD as DAC. I use Roon (mostly) and Sense as streaming software. Not long ago, I did some tests to see the behavior of the sound in Roon, placing a Roon Ready to act as a bridge between my Innuos combo and the Esoteric Dac. From those tests, the conclusion I've come to is that a good streamer bridging can go a long way in SQ quality. The best result was when putting as Roon Ready an Esoteric N05 (previous model) and connected by coaxial to my DAC. For this reason, I have been looking at the options for a good streamer, including the N05, or the Hifi Rose 150, the Metronome DSS 2, and in that order of things I found the Grimm Audio MU1. That is a brand that has caught my attention for its good reputation in synchronization cloks.

That's why I was wondering how the coaxial output of the MU is, if it's as good as AES. The idea of ​​a MU1 would also be due to its SQ quality for removing two devices from the system, which is why I am concerned about the comments about the need to place an ethernet filter/recloker before the Grimm.

@peter_s I do not hear a difference when using fixed vs variable volume on the MU1.  But that said I’ve been using it with the volume control disabled.  I’m going to look up that statement you referenced in the manual - what page/section is it in?


I have owned all three NA Ethernet product ranges and can confidently tell you the Pro delivers much more sonically. I like the ENO products as they certainly improve the sound quality of a streaming front end. The Pro makes the ENO sound a tad dull in comparison. Not that the ENO is dull as it is not. However, the Pro brings a level of resolution, space and realism that is very, very special in my system.