Home Review Grimm Audio MU1

Review Grimm Audio MU1



  • Sounds fantastically neutral
  • ... and stressless
  • Versatile


  • Software here and there quirky
  • Pricey device

Price: € 10000

App - Software
Grimm Audio MU1

The sound of...


The sound of the Grimm MU1 is… very difficult to describe frankly. We listened extensively to the Metrum Acoustics Ambre next to the MU1. And at first there seems to be very little difference. But that’s a bit of a deception, because time and again we hear the same things coming back: neutrality, extra resolution and above all: more spacial information.

Those who are serious about listening and not only pay attention to timbre, but also experience, air and ‘authenticity’, will soon notice that there is the unique feature of the Grimm Audio MU1 lurks.

And after a few days it is striking how easily the Grimm Audio MU1 plays. Everything comes through smoothly, naturally and in the right proportions. The whole thing is stress-free… If we then switch back and forth a bit, we notice that our ears prefer the MU1. We get less listning fatigue. And of course this is about small things, because honestly: the Ambre is a pearl within its price range. But the fact is: the Grimm Audio MU1 goes one step further. And it has to: it costs about eight times more.


Let’s get back to the experience. We’ve picked up a selection of test numbers. A mix of pop, classic, live and studio. It is noticeable that the Grimm MU1 shows how the track was recorded over and over again. It sounds live. It Includes the space, acoustics, the audience and the energy that goes with it. That’s really impressive, because the energy in particular ensures that a piece makes impact. It’s hard to turn Steven Wilson live at the Royal Albert Hall off. That because we just hear the Royal Albert Hall. It’s a great experience. Pulling out these last bits and transferring the musical energy and feeling is an art… an art few manufacturers master.

Time for some piano work. We start with a piece of Jeroen van Veen. The series by Einaudi: Waves. The Ambre presents the whole thing neat and tidy. Exactly as we know it from our system. Neutral, airy, quick… Then time for the Grimm Audio MU1. Yeah. It’s adding a little extra on top of that. Especially the extra harmonics that belong to the touch of a piano note. It adds some extra beauty. Something the Sopras willingly show.

Also a bit of edginess in the higher octaves is lost. This makes the sound no longer ‘frayed’ (ringing), but very fluid. Though we have to say that frayed might be a bit of an exaggeration. At this level it’s all about nuances. But nuances that provide an extra experience. And music is about perception, isn’t it?

If we think about it that way, the Grimm Audio MU1 may be able to touch the essence of the music better. The core… the soul… the emotion. Can we call that subtle? No. Definately not.

All sources

We also briefly tested the inputs. We connect the Ambre via AES to the MU1 and a Sony 810 blu-ray player via spdif to the Grimm hub. We then play a few tracks via the MU1 and compare that with a direct link to the Pavane-dac. And damn… we hear through the MU1 the quality of… yeah, the MU1 back. The Sony also sounds considerably better via the MU1 than directly via the converter. That’s really impressive and shows that this statement by Grimm is not marketing. It’s just instantly audible that the FLL clock and upsampler just work.


  1. Hi Jaap, great review.

    I know you have reviewed both the MU1 and Weiss DAC 501. I’m wondering if you had ever paired the MU1 with the Weiss and could offer your impressions? I have a Weiss DAC501 Mk 2 version and am very interested in the Grimm product.

      • Jaap, I am currently in the process of sourcing a few AES/EBU cables to use for connecting my Weiss 501 to the Grimm MU1 (I now have one on order which will be delivered in about 2 weeks :).
        I’m wondering of you have any feedback on the following few cables which I so far plan to trial – Transparent Reference G6, Nordost Valhalla 2, Cardas Clear? Or, do you have any other suggestions you recommend are worth a listen to?. FYI, the interconnects I have from my Weiss to my Genelec G5 speakers are Cardas Clear Beyond balanced XLR cables, which were sublime to my ears.

          • That’s ok Jaap:) Ultimately it will be my ears that decide in the end. But I thought it was definitely worth asking you just in case you have ever found a certain cable that was extraordinary from your point of view, and hence worth adding to the list to explore.
            I will be happy to share with you how it all goes!