Country of Origin



Reviewers: Marja & Henk
Financial Interests: click here
Sources: PS Audio PWT; Dr. Feickert Blackbird MKII/DFA 1o5/Zu DL-103
DAC: Mytek Brooklyn; Mytek Brooklyn Bridge; T+A DAC8 [loaner]; TotalDAC D1 Direct [loaner]
Streaming sources: Devialet AIR; La Rosita Beta; Qobuz Desktop, Tidal Desktop; Sound Galleries Extreme [loaner]; Grimm Audio MU1 [in for review]
Preamp/integrated/power: Audio Note Meishu with WE 300B (or AVVT, JJ, KR Audio 300B output tubes); dual Devialet D-Premier; PTP Audio Blok 20; Hypex Ncore 1200 based monoblocks; Trafomatic Kaivalya; Trafomatic Reference One; Trafomatic Reference Phono One; Music First Passive Magnetic
Speakers: Avantgarde Acoustic Duo Omega; Arcadian Audio Pnoe; Podium Sound One; WLM Sub 12; Sounddeco Alpha F3; dual Zu Submisson MKI; Soltanus Virtuoso ESL
Cables: complete loom of ASI LiveLine cables; full loom of Crystal Cable cables; full loom of Nanotec Golden Strada; Audiomica Pearl Consequence interconnect; Audiomica Pebble Consequence USB; Audiocadabra Ultimus3 Plus Dual-Headed Solid-Silver
Power line conditioning: PS Audio Powerplant Premier; PS Audio Humbuster III; IsoTek Evo 3 Syncro; AudioMica Allbit Consequence
Equipment racks: Solid Tech and ASI amplifier and TT shelf
Indispensable accessories: Furutech DeMag; ClearAudio Double Matrix; Franc Audio Ceramic Disc Classic; Shakti Stones; Kemp polarity checker; Akiko Audio Corelli,Costello and Phono Booster; Pink Faun LAN Isolator; Farad external power supply
Online Music purveyors: qobuz.com, tidal.com, bandcamp.com, amazon.co.uk
Room treatment: Acoustic System International resonators, sugar cubes, diffusers
Room size: ca. 14.50 x 7.50m with a ceiling height of 3.50m, brick walls, wooden flooring upstairs, ca 7 x 5m with a ceiling height of 3.50m, brick walls and concrete floor downstairs.
Price of review item: €9'800

Grimm Audio made real audio history with their original CC1 master clock. This ultra-precision device is still used in many studios around the world and responsible for musically coherent timing just as it is for musical tone stability. The relevant word is jitter and fighting it to the death is at the core of Grimm Audio. Jitter influences stereo imaging, timing and tone. It's caused by power supply noise, oscillator noise, even cross talk. To combat it, Grimm Audio developed the most stable possible clock based on a discrete crystal oscillator.

At Grimm's where valve amps double as wall art.

Humans are blessed and cursed with fabulous hearing sensitivity. But good hearing certainly doesn't imply good listening skills. Our hearing detects the smallest imperfections. Once this detection becomes part of our conscious listening, we can't un-hear it again. Basically, digital audio guarantees perfect copies. However, when the digital format is converted and resampled to either another digital format or analog, things can get lost in translation. Unpacking digital for actual consumption can easily lead to imperfections.

After their CC1 clock, Grimm Audio created the LS1 range of active speakers. Radically different from conventional loudspeakers in looks and tech, these were welcomed not only in professional studios but demanding consumer settings. We enjoyed reviewing a few versions of this remarkable loudspeaker system. When looking at the consumer market next, team Grimm saw a real need for a music source which not only exploits their digital know-how and philosophy behind the LS1 loudspeakers but goes beyond. That became the MU1. It's not a streamer in the conventional sense. The MU1 plays music from various digital sources, then adds something quite unique. The MU1 helps offload a DAC's heavy calculations when the latter converts music data from the digital into the analog domain.

To meet this task, the designers at Grimm split the MU1's duties in half. One became the more standard set of tasks which a computer involved in audio playback handles. It oversees the i/o, the interaction with the network, the user interface and local/remote storage. For that Grimm partnered with Roon Labs whose Core Server and End Point are factory installed and whose processing is performed by a custom Linux operating system and its hardware. The other half is a Grimm-designed/built field programmable gate array. This custom-coded FPGA is programmed to perform the absolutely best resampling possible. Of course the MU1 also contains the most stable clock so that jitter has no chance of interfering with creating the best digital output conceivable.