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...




Updates! First, I fixed my MU1’s hard disk myself. After Eelco mentioned in his note that the issue may be related to the hard disk’s USB connection not being connected, I thought that would be the simplest thing to fix. So tonight (while watching M3gan with my daughter, so I desperately needed something to do while enduring that pain…) I opened the chassis, and sure enough, the USB connector wasn’t inserted in the PCB’s port. Plugged it in and problem solved. And I got to check out the inside of the MU1 and snapped some pics of the PCB’s and cabling.

Second, I disabled the MU1’s volume control. I don’t know if this has a positive impact on sound quality, as it apparently does with some DACs.

Third, I toed in my speakers quite a bit more.

The results are breathtaking. Everything on the MU1 sounds absolutely perfect now. Soundstage depth is full, even and natural now. And vocals are spectacular and intimate. Like a “window into the recording studio” as some have said. The level of of precision is stunning. I think Innuos still has a more full body but this is bloom which is not as realistic. The 4X OS is more noticeable over NOS now - but still more subtle than I expected. It’s as if some barriers are removed and everything becomes ever so slightly more free and extended. I hear it in the upper mids and treble the most - becomes sweeter and more free sounding. Punk and grunge music with blaring guitars sound absolutely vicious in such a good way. All this detail and it’s really the opposite of fatiguing.

Tonal balance on my overall system sounds great - overall full balance with lots of bass that is so, so well defined and controlled, and as I mentioned before the impact and slam is just way more solid than my Innuos setup at all frequencies. Price point wise, not factoring the added cables, the Zenith Mk3 and PhoenixUSB cost a bit less than the MU1. But the MU1 still costs less than an Innuos Statement (non Next-Gen).

Another thing. As I mentioned I’ve been having issues with poor quality power lately. Yesterday around dinner time was the absolute worst I’ve ever heard - everything became a soft spongy mess while I had my Innuos gear running. Not enjoyable to listen to. Switched it over the MU1, and it sounded like music again. There was enough separation and impact that the MU1 was able to cobble together a coherent musical presentation with a worst case poor quality power scenario.

I think the speaker placement adjustment made a huge difference. Was needed to deal with all the extra detail that is coming through now.

Pretty happy with the MU1 at this point! The detail and impulse control reminds me of what is more easily achieved with an excellent headphone setup. Which is not easy for a full system to be able to do. And most importantly it’s very, very musical -  however you want to define that.  For me it means it sounds like people making music that conveys emotion and a feeling, as opposed to a HiFi system. Not dry/cold/analytical/lean at all!




Glad you are enjoying your MU1 and Tambaqui combo. I have the same setup and love it. Give your MU1 and AES/EBU cable a couple hundred hours of break in. It will get fuller and better tonally without losing that openness and detail. The dynamics and bass detail is great! It really controls the bass wonderfully and vocals will come around with more hours on it. 

On Qobuz check out Dan Patlansky: Wooden Thoughts Album, songs Big Things Going Down and Hallelujah. The guitar sounds so real with great dynamics, bite, and feel. It sounds awesome! Streaming sounds really good, if the recording are well made!

Hi @nyev,

Thanks for the great update!  Is this update still with your “basic old cheap” Cardas AES, and AQ Red River ICs?

@snopro thanks for the tip I will check out those songs on that Dan Patlansky album. In general the texture and sizzle of electric guitars is more alive sounding than I’ve heard on a full system before.

@rockrider , yes this update is with my basic interim cables still. I’ve since moved my speakers slightly apart and the sound has become bigger in scale with even more depth and dimension. As good as it was before it’s sounding even better now.

I really respect Innuos a lot and don’t want to make it seem like Grimm is good and Innuos is not, because that’s not the case. The Innuos setup has a charm to it that the Grimm doesn’t have. With the Tambaqui, Innuos is very clean and smooth, but with a large-scale overall presentation, and again that forward presentation of the mid and upper ranges. Presence.  Yes, that’s it! The Innuos setup does exceptionally well with presence, ambience, and scale.

But while the MU1 may not have these qualities quite to the same degree, it heads in a totally different direction - stunning detail, tangibility, solidity, impact, and music that is totally alive and captivating with more athletic drive to it. And I get more of a feeling of people playing music as opposed to listening to reproduced music.

A few posts ago I mentioned that eighties albums (like Bowie’s) that have a narrower presentation of vocals sounded even narrower with the Tambaqui. This was when driven by Innuos. With the MU1 and the Tambaqui, that problem is non-existent and Bowie sounds natural (or at least as natural as Bowie can sound…) One track that accentuates this is Bowie’s “Panic in Detroit”. Vocals sound free and not constrained to a narrow presentation, and wow the bite and snarl on the guitars are just incredible, especially with the dual distorted guitar tracks on the left and right through the outro.

I don’t think the Tambaqui and MU1 are going to be liked by everybody and it’s going to be system dependent. If the rest of my system was neutral, I possibly may have found the Tambaqui/MU1 too lean. But my Diablo 300 adds a richness without losing detail that is just right for me. There is a rawness that I just absolutely love, but some may prefer a smoother less textured presentation like what the Innuos does. Don’t get me wrong when I say raw I don’t mean harsh, not by a longsshot. I mean that the detail and texture is fully intact. But the presentation is so relaxed and unforced yet hard-hitting at the same time, and this makes it all so easy to listen to for hours on end. If you are a whisky drinker, it’s sort of like some who prefer Johnnie Walker Blue with some ice and love that it is “smooth”, vs others who prefer a well-aged single malt that is packed with character, unchill-filtered and bottled at cask strength, with no ice and just a few drops of room temperature water. If you are into whisky you know what I mean. Both styles are valid and cater to a different audience. Also to be clear I don’t mean to compare Innuos with Johnnie Walker Blue, that would be unfair to Innuos, lol…. Innuos has far more going on than that. But it’s a good example to explain the distinction.

At this point for me I don’t think there is any ambiguity as to my preference but I’ll give it a few weeks and go back to Innuos to be sure.

And to reiterate - all this is with my interim, lowest level basic AES cable and balanced interconnects. So things will likely shift dramatically again when that changes in a few weeks.



@snopro just listened to those two Dan Patlansky songs (Hallelujah and Big Things Going Down). You are right, the texture and grit makes it sound so realistic. I’d say it sounds like the guitar is here in my listening room if it wasn’t for the reverb or ambience in the recording.  Good chill music for late night.