⌈ The idea for the LUMÏN company was born in 2010, and the impulse for it was the discovery of a way to extract DSD signal from SACDs. Their main field of interest is playing audio files. The brand belongs to the Hong Kong-based company Pixel Magic Systems Ltd., which specializes in HD video playback and processing. We are testing its latest product - U2 MINI, a transport of audio files. ⌋

UMÏN'S LATEST PRODUCT is described by LUMÏN as "fantastically intuitive and easy to use". And no wonder. U2 Mini is an audio file transport controlled by a proprietary application, that’s been developed by the company for years, which is one of the best on the market. What's more, all the basic information can be read from the quite transparent display on the front of the device. It is not a display of quite the same class as one used by AURENDER or Rose, but it is OK. Lumïn focused primarily on communication via the application.

▌ U2 Mini

U2 MINI IS A TRANSPORT OF AUDIO FILES. Users recruiting from computer circles will talk about the "end-point", which is also promoted by Roon. Don't get caught up in this, it's just a marketing handle. What does file transport do? - It reads AUDIO FILES from internal or external media, decodes them and converts to audio DIGITAL SIGNAL. Treat it like the 21st century version of a CD transport.

U2 Mini does not come with a storage medium (it does not have a built-in hard drive), so you have to "feed" it from the outside. We can do it directly by connecting a USB drive or pen drives to it. The device is equipped with two USB ports, one of which is used to send a signal to an external digital-to-analog converter, and the other act as an input for a storage medium. The preferred method, however, is to feed it files from a NAS disk, i.e. via Ethernet connection, or from one of the streaming services.

The control application supports TIDAL streaming service - with MQA decoding - Qobuz and TuneIn internet radio. It also offers volume control, enables upsampling (separate settings for each sampling frequency), etc. The volume control called Leedh Processing is carried out in the digital domain and the manufacturer calls it "lossless". Speaking of upsampling - the U2 Mini, although small, offers extensive possibilities, because the DSD signal can be upsampled to PCM 348 kHz or DSD256, and PCM 16/44.1 to DSD256 or PCM 348 kHz, with all intermediate values.

| Processing

⸜ U2 Mini’s new processor – under a radiator – next to a RAM chip

ONE OF THE MOST IMPORTANT factors shaping the capabilities of file transports and players is the processor used in them. In fact, they are specialized microcomputers that usually run on Linux. Newer, faster processors allow you to play a wider variety of files, and also allow you to perform other operations. Lumïn uses it for upsampling and volume control. However, it is worth remembering that the harder the processor works, the higher the jitter is generated. Therefore, it is worth checking whether disabling all these options improves the sound.

Due to the fact that the device is equipped with a completely new processor, much more powerful one than in older devices, it plays DSD files (DSF, DIFF, DoP) up to DSD512 and PCM (FLAC, Apple Lossless [ALAC], WAV , AIFF) up to 32 bits, 768 kHz, as well as MQA. The company says, that it is its first product with such a powerful computing system (microcomputer). Four separate clocks are used to clock the signal so that the signal is as little prone to jitter as possible. ♦ ♦

WE CAN SEND EITHER PCM or DSD DIGITAL SIGNAL from U2 Mini through five digital outputs: optical TOSLink, coaxial RCA and BNC, balanced AES/EBU and USB. The latter supports a full range of signal types, up to DSD512 (natively) and PCM 32/768 (although I have never seen such PCM files; DSD512 do happen). In turn, the other four offer DSD signal in DoP (DSD-over-PCM) and PCM format up to 24/192.

The transport is powered by a classic AC power cord, because the power supply is installed inside it. It is an SMPS, developed by the Lumïn company. There is also a ground terminal on the rear panel - it is worth connecting it to an artificial ground - just like I did. U2 Mini may be a "mini", but feature wise its really a "maxi" device :)

▌ SOUND

˻ HOW WE LISTENED The LUMÏN U2 MINI audio files transport was placed on the top shelf of the Finite Elemente Pagode Edition Mk II rack. Under its feet I put ACOUSTIC REVIVE RPI-5005 washers. On its top I put the Verictum X Block passive EMI/RFI filter. I used the second such filter as the basis for the USB drive.

The transport was connected to the Internet via my system consisting of a double LAN SILENT ANGEL N16 LPS switch, with its two modules in series, powered by a TIGLON TPL-2000A cable and a TIGLON TPL-2000L LAN cable; you can find more about it HERE |PL|. The signal was decoded in the D/A converter sections of the SACD AYON AUDIO CD-35 HF EDITION player and the MYTEK BROOKLYN BRIDGE file player; I also used the MYTEK LIBERTY DAC II D/A converter.

During playback, I did not use the internal volume control or upsampling. The transport was powered using the HARMONIX X-DC350M2R IMPROVED-VERSION cable.

˻ Recordings used for the test | a selection

⸜ PERRYCOMO, It’s Impossible, RCA Records/Tidal Master, FLAC MQA Studio 16/44,1 (1970/2008).
⸜ RÖYKSOPP, Profound Mysteries, Dog Triumph/Tidal, FLAC 16/44,1 (2022).
⸜ J.S. BACH, The Well-Tempered Clavier. Book 2, BWV 870-893, wyk. TREVOR PINNOCK, Deutsche Grammophon/Tidal Master, FLAC MQA 24/192 (2022).
⸜ SOUNDGARDEN, Superunknown, A&M Records/Tidal Master FLAC MQA STUDIO 24/96 (1994/2014).
⸜ ARNE DOMNÉRUS, Jazz At The Pawnshop 30th Anniversary, Proprius PRSACD 7879, rip z SACD (1976/2007).
⸜ ARCADE FIRE, WE, Columbia/Tidal Master, FLAC MQA Studio 24/96 (2022).

IF SOMEONE CLAIMS THAT only the DAC counts when playing audio files, then they have no idea what they're talking about. When I wrote something like this for the first time several years ago, I was perceived as an idiot, or at best a harmless eccentric. Today, manufacturers offer a whole range of this type of transport, in various price ranges, from PLN 1,000 to PLN 100,000. If transport didn't matter, the "cheat" would be easy to prove and you could settle for a laptop.

In fact, transports, ie devices that read physical media or decode audio files, are a key component of any system. Which is reminiscent of the well-known phrase of the Linn company, which already in the 1970s used to say: "source first". That is why Lumïn pays so much attention to power supply, clocking and processors, going hand in hand with the giants of our industry, such as the already mentioned Linn or Naim Audio. Because it is such an important element, any change in its design also changes the sound. This is also the case this time.

The U2 Mini sounds different than the earlier files transports from this manufacturer, as well as what they proposed at the beginning and what they built their brand on. Instead of "sweetness" in the new device we get an opening, instead of dense and warm colors, dynamics and powerful extremes of the sound spectrum. Because the dynamics and energy that the U2 Mini offers are the most important features of this transport. Interestingly, these are the elements that are usually the "soft underbelly" of devices used for playing files, and even more so for streaming.

They could be easily attacked there because they had nothing to defend themselves with. Any CD player of any kind, not to mention a turntable, could beat them in this respect. The tested transport is different, and this change began with, as far as I remember correctly, the T2 player. And this dynamics, momentum and fullness are with us regardless of what music we listen to, as long as it is sent via the RJ45 (Ethernet) input.

If you think about it, it makes sense. After all, the vast majority of music lovers and audiophiles today use one of the streaming services, be it Spotify, Apple Music, Tidal or Qobuz. And it was they who benefited the most from this change. Both PERRY COMO from It’s Impossible and RÖYKSOPP from Profound Mysteries were shown with nerve and dynamics. It is not the nerve and dynamics that can be obtained from CDs and SACDs, but without direct comparison it will not be an issue.

The Lumïn does it by bringing the foreground closer to us and shortening the decay. At the same time, however, it does not "impose" the sound on us, because it is not as dense in this proximity as a turntable. U2 Mini does not pretend to be an analog medium, but tries to play digitally recorded music in such a way as to get as much energy as possible from this medium, especially when streaming. That is why we get a clear sound image, both with a refined recording of the J.S. Bach’s The Well-Tempered Clavier. Book 2 performed by TREVOR PINNOCK and with the Black Hole Sun by the SOUNGARDEN.

I verified these observations by listening to music through headphones. It is then that even the smallest changes in the sound - apart from spatial relations, which are obvious - are best heard. Therefore, I knew that the device offers a low, very low and full bass, like at the end of the first minute of the opening track of the already mentioned Röyksopp album. It was great! It was similar with the high tones, which were sonorous, strong, dynamic and open, which was confirmed by the opening fragment of the High Life from the Jazz in the Pawnshop.

At the same time, however - and this was the most important thing when listening through headphones - the band extremes never dominated and were not emphasized. The presentation was not "tangible" or filled, as with the older devices of this company, you have to know that. Also the CD and SACD discs show both of these elements in a better, more resolving, way. And yet it is a saturated and dense sound. This effect was achieved, however, not by the density of the timbre, but by saturation with details, and small elements, which in the previous generations of the Lumïn were "buried" in a dense presentation.

Therefore, the sound of the U2 Mini seems to me to be a very good compromise between palpability and distance, as well as between detail and richness. It showed beautifully, for example, with the latest album of the ARCADE FIRE entitled WE, where, on the one hand, I had a dynamic presentation, and on the other, it was toned down and not "thrown in the face". So it can be said that it is a dynamic, but also calmed down sound; open, but also toned down. It is a very good combination when playing files from streaming services.

▌ SUMMARY

AND THAT’S HOW I UNDERSTAND THIS DEVICE: not as a high-end transport that is supposed to match CD players, SACD players or a turntable, because it will not do it. If we approach it this way, we may be disappointed. However, if we want to stream music in the coolest, calm, but also open and dynamic way, it is a device for us, because it does it very well.

Files listened to in this way will never sound aggressive, but also will not be warm or "muddied". The foreground will be presented quite close to us, and the decays will be shortened, but it will not be a on-the-face sound, but a nicely distanced one. The designers of the Lumïn U2 Mini managed this combination of opposites brilliantly.

▌ DESIGN

LUMÏN U2 MINI IS A TRANSPORT OF AUDIO FILES. It is small, measuring just 300 x 244 x 60 mm, does not weigh too much at 2.5 kg, so it will fit not only large audio systems, but also "desk", or bedroom ones. Its appearance repeats the design line known in Lumïn for years, but the designers tried to make the finish better than before and used the solutions they used for the P1 player.

The chassis is made of aluminum, bent elements and a flat fragment forming the front baffle. There is a blue filter display where we can read a lot of information, although it's not too big. The S/PDIF (RCA and BNC) and AES/EBU sockets look very nice, hidden under the rear top and side panels. The others are classic for industrial devices. The device rests on flat feet made of felt-backed aluminum.

The electronics elements are mounted on a single, multi-layer printed circuit board with the proper file transport section, i.e. a microcomputer, connected to it. The processor is cooled by a small passive heat sink. After decoding the files, the digital signal, both PCM and DSD, is sent to the main board, to the Altera Cyclone IV DSP. As I understand it, Lumïn engineers included algorithms for volume control, MQA decoding and D/D conversion, i.e. upsampling. In front of the digital outputs, you can see the output impedance matching transformers.

On the side there is a universal switching mode power supply, which replaced the linear power supplies in Lumïn a few years ago. It has been closed in a box that shields it and is a company's own in-house development. ■

▌ Technical specifications (acc. to the manufacturer)

Supported: native up to DSD512 & PCM to 768 kHz, 16–32 bits | MQA
Supported file types:
• DSD: DSF, DIFF, DoP
• PCM: FLAC, Apple Lossless (ALAC), WAV, AIFF
• Lossy file types: MP3, AAC (M4A)
• MQA
Upsampling: to DSD256 or to PCM 768 kHz
Digital outputs
• USB: native up to DSD512 | PCM 44.1–768 kHz, 16–32 bits
• BNC, RCA, AES/EBU S/PDIF: PCM 44.1 kHz–192 kHz, 16–24 bits | DSD64 (DoP64)
LAN input: SFP | 1000Base-T Gigabit Ethernet
Dimensions (W x H x D): 300 x 244 x 60 mm
Weight: 2.5 kg