The Lumin D1 measures 240 x 244 x 60mm WxDxH, therefore is smallest in the line-up. It weighs roughly two kilograms. Practice shows it's a handy light box yet solid built and fancy looking - clean so to speak. All Lumins are. The industrial design is very simple, therefore universal and stripped of all bling. The aluminium front is a bit bigger than the rest. A monochromatic non-touch blue-on-black display is placed centrally and shared amongst all Lumin models. The sides and top are one U panel made from brushed aluminium. The bottom has four rather large plastic feet with rubber pads. Ten screws are seen there to keep the design in one piece. When looking at the back, the chassis extends a bit over it for a purely aesthetic effect. All connections are less visible, therefore show off less cable jewelry for a more minimalist coherent look. Yet it's quite difficult to manage XLR locks. That’s merely a small inconvenience when in the vast majority of scenarios, the machine is connected once and not touched for a long time thereafter. The D1’s back is richly socketed. On the left side are analog RCA (2Vrms) and XLR (4Vrms) outputs. Digital BNC out and grounding screw are next. RJ45 Ethernet socket, two USB type A digital inputs, a reset button, PSU input and on/off switch complete the picture.

To some people the lack of coax and TOSLINK might be a disadvantage but there was no more room. The D1 is small after all. Thanks to a cheap BNC/coax adapter, one problem can be solved rather quickly. Lots of sources have physical volume control, knob or button based. The D1 does not. It’s hard to see this as a flaw. The majority of people interested in the D1 will hook it up to separate preamplifiers or integrated solutions. Some would like to have a remote with physical buttons. But again, practice shows in painfully obvious ways that any iPad fulfills that role extremely well.

Let's take a look at the innards. One big PCB covers it all. Right behind the digital outputs there's a Wolfson WM8805 as S/PDIF transceiver. A Realtek RTL8201CP takes care of the RJ45 in. There's also an FPGA underneath a large aluminium heat sink. It's hard to say what role it might serve, exactly. Anther FPGA, this time identifiable, is a Cyclone VI by Altera. Both of those logic chips handle signal before it gets to the D/A converters. But how that is done remains a mystery and let’s keep it that way. One recognizable function is obviously upsampling. At least that's what the Lumin app suggests. The last stop is a WM8741 Wolfson DAC per channel. Thanks to those, the D1 is DSD64 capable in native mode and can also handle 32/384 PCM. To paint the larger picture, Lumin’s flagship S1 has four Sabre ES9018 DACs and is DSD128 capable. In the D1, just after the converters there are Texas Instruments L49860 operational amplifiers, two per channel as low-pass filters. Capacitors are WIMA FKP2 and Nichicon Muse series. The entire analog part is balanced and the manual recommends the XLR as the preferred connection type.

D1 configuration is easy. In fact, you needn't do anything special to make it work. The device wants DLNA-capable NAS storage. A computer with JRiver will do the trick. Some people might get scared as network-related actions often require knowledge. Not this time. Dealing with the D1 is nothing fancy. Automated things self-start, no user-based configuration is required safe for a few mouse clicks. The Lumin needs to be connected to the router via wire since it doesn't have a WiFi receiver. Next, the Lumin app should be installed on an iPad, the music library picked from the obvious place inside the options. That's it. Plain and simple. On a side note, wired router mode is mandatory. Without it, a network error message pops up in the display. For the vast majority of us, there's unfortunately no way to avoid those pesky Ethernet cables. [Some of us who despise WiFi consider it fortunate - Ed.]   

User can also avoid a NAS or computer entirely.The flat USB sockets become hosts for pen drives, memory cards or SSD/HDD. Just to make it even easier, the D1 will work with FAT32, NTFS or EXT2/3 formatted memory devices. Once storage is attached, you show the app from what source the media library should be loaded. Then indexing happens, the time for it depends on the added library. Usually things happen quickly. Once again, the entire process is a walk in the park. Be aware though that at present, the Lumin app is reserved for iOS devices. From what is known, Android-based tablets will get their moment soon. The program itself is great, very friendly, responsive and stable. Certain options might be turned on and off, i.e. volume control or digital out. Also, PCM upsampling is handled discretely for each sample rate, starting at 44.1kHz and ending with 384kHz. DSD playback too is selected manually via bitstream, DoP or PCM. The available options will cover the needs of most. Lastly, the user chooses music via filtering or finding, not by accessing the file folder structure directly. Many folks aren't used to that, including yours truly. But Linn’s Kinsky app can add that functionality where direct folder access is allowed.