I had the Lumin D1 on loan from a kind friend for a week. I walked away with a very good impression of the D1, especially for it's price tag (about S$ 2,000).
The D1 is an affordable music streamer that can either stream from a NAS, or removable USB storage. An onboard DAC makes this a one-box solution unlike it's competitors from Aurender and Auralic.
Control is via Lumin's iPad app. At time of writing, official versions for other platforms were not available.
Compared to Lumin's more expensive models, the D1 omits battleship construction, and utilises a single circuit board housed in a more compact chasis. You still get dual Wolfson WM8741 DAC chips and balanced outputs though. A switched mode power supply is provided. However, my friend had purchased a balanced DC power supply from Sound Affairs, and I used that during the time I had the D1.
Looking at pictures of the internal layout of the D1, the analog circuit omits the Lundahl output transformers in pricier models, and the separate hollowed out sections in the case. Part quality remains high. There are six green electrolytic capacitors (i am pretty sure these are Nichicon Muse BPs) towards the rear of the board (presumably to serve as coupling capacitors). There is also a pulse transformer near the BNC digital output which provides galvanic isolation.
The Lumin has no remote control, which leaves you reliant on it's app (or another third-party compatible app) to control it.
The Lumin app allows a high degree of control over the D1, including a variety of upsampling and downsampling settings. You can even set the D1 to transcode DSD files to PCM on the fly (for the digital output), which allowed me to playback DSD files on my Calyx Femto DAC which is not DSD compatible - very useful.
I currently use the Auralic Aries and some quick comparisons in the features department would be in order.
The Aries comes with a remote control (which can only control very basic functions), and has more flexible digital output options (e.g. USB, coaxial, Toslink and AES/EBU). The Aries also has a built-in wi-fi module to hook up wirelessly to your NAS, in addition to an Ethernet port for wired connection.
The D1 in comparison has a single digital output in the form of a BNC socket. Network connection is via Ethernet only. I strongly preferred the display on the D1, which displays track information, elapsed / remaining time, file format, bit depth and sampling rate. The Aries only tells you the number of tracks in the playlist, the track number being played, and elapsed / remaining time - not particularly useful information if you ask me.
Both machines can play from attached USB storage such as a USB hard disk or thumb drive, making a NAS unnecessary.
The D1 has more solid build quality - aluminum vs the plastic casing of the Aries (a necessary evil for wi-fi transmission according to Auralic).
The D1 has a warmish balance. Bass notes have a nice bloom to it, with a slightly rounded and organic quality. Midrange has a similar light golden hue to it. It is not overtly warm, but with a slight liquid and smooth feel. Female vocals have a bit more body that usual, while there is some smoothing over of vocal texture and sibilance. HIgh frequencies are well-behaved and detailed, but with some subtle reduction in decay and ambience.
Soundstaging and imaging are good, although depth was a little bit lacking compared to soundstage width.
The D1 has above average resolution and maintains good separation even during busy moments. Tonally, it has a "chunkier" feel, and sonic images have a degree of solidity and weight to them.
I would even dare say that the quality of the onboard DAC alone is probably worth more than the D1's price tag, and fully up to scratch as a source for midrange and even entry-level high-end setups.
From an absolute viewpoint, the D1 is not neutral and trades a bit of resolution for a flattering and easy-going presentation (many of my mangled recordings sounded quite palatable through the D1).
Used purely as a "transport", the D1 can deliver higher performance if paired with a better DAC. It sounded better connected to my Calyx Femto DAC, improving all round, but most noticeably in bass extension and microdetail. Interestingly enough, the warmish balance and midrange liquidity carries over to the Calyx too.
I still feel that the Aries outperforms the D1 used as a transport, but the Aries carries a similar price tag, while devoting the full budget to it's streaming circuit and digital outputs. I think either devices are a good bet, depending on user needs. The D1 is a great single-box solution, while the Aries would be perfect for someone who already owns a good DAC.
The Lumin D1 is a very competent and affordably priced component. I can only imagine how good the higher range A1 and S1 may be.
Lumin is going to have it's hands very full trying to keep up with demand for it's new baby - Highly Recommended.
Thank you CS, for the loaner !