Martin Mertens of the German online magazine Fairaudio wrote a review of the MU2. He was impressed by the total transparency of the MU2, that lacks any character of its own and thus steps out of the way of the music.
“It’s slowly dawning on me that the Grimm Audio MU2 is probably one of the most transparent components I’ve ever had in my listening room. I’ve rarely had the impression of hearing so much of the recording and so little of my playback chain as with the MU2. (…)
In the bass, the Grimm MU2 has total control. Always. At least, as far as the recording has it and the rest of the system allows it. Whether it plays the synthetic bass worlds of M83 or Silicon Soul, or the timpani and drums in Stravinsky’s Le Sacre Du Printemps, or the rumbling double basses in Edvard Grieg’s Peer Gynt – the MU2 passes through what can be passed through, without any detectable interference or restriction. (…)
Concerning the mids, I would venture to say that it can hardly be better – at least when it comes to passing on what the recording has to offer clearly and unerringly. (…) I could write a lot here, but it would only characterize the recordings and not any sound properties that could be assigned to the MU2 – at least that’s my impression. And the same applies to the highs. (…)
The MU2 is a precision tool. It definitely knows how to deal with high-resolution material. I find high-resolution digitized vintage recordings particularly interesting in this context. Oscar Peterson Exclusively For My Friends for example has a lot to offer. The live recordings of a series of private concerts recorded between 1963 and 1968 in the studio of MPS founder Hans Georg Brunner-Schwer are remastered and available in DSD quality. The remastering was done very carefully and many of the qualities of the original were exposed. Listening through the MU2 becomes a kind of time tunnel that takes me straight to the MPS founder’s villa on Lake Zurich. I have never experienced old recordings like these as multifaceted and authentic as I did through the MU2. (…)
The MU2 renders the recording’s spatial characteristics to a degree that I rarely heard before. (…) It conveys the spatiality that was captured on the recording into the listening room, seemingly one-to-one. Whether it is small and concentrated, cinemascope-wide, live with a lot of atmosphere, or holographically precise – the MU2 reveals all of it.“
“The MU2 is by far the most neutral digital source I have come across so far.”
Martin Mertens, Fairaudio, Germany