Cos célèbre? My FedEx shipment picked up on a Monday in the Hien Tsien district of Taiwan. It departed Asia in Guangzhou/China before touching down in Europe. This meant Köln, Paris and Stansted in the UK before hitting Dublin. By Tuesday the following week it had cleared customs in our western airport of Shannon. It was on the delivery truck by Wednesday. To remind ourselves of its bigger D1 brother, here are photos from Dawid Grzyb's March 2016 review.

The D10 revisits its lower-edge bevel for a continuous look but adds many features including a display to allow precisely repeatable volume settings. The buffer on/off toggle also made the transition. You'll defeat it for perfect lip sync with video where buffering incoming digital data for sound incurs a small time delay against the visual data.

The USB 1.0/2.0 toggle didn't migrate over so Windows users must install a USB driver. The D10's I²S-over-HDMI port is new. So are AES/EBU and S/PDIF on BNC rather than coax. Analog i/o on RCA and XLR are as they were on the D1, just in a different layout.

What's new again and wasn't yet on first D10 prototypes is the deeply etched COS logo on the top. That multi-tasks as legible venting. This classy sculpted FMJ remote with eight buttons but now bigger IR eye controls standby, mute, ± source and volume, info and display dim.

By giving up on milled-from-solid coin, now the top cover is far thinner hence ringy when tapped. If  that bothers you, do a John Darko. Buy a door stopper. For a few euros, it'll add stylish mass loading.

Once plugged into our music iMac with Audirvana 3.5, the software player immediately recognized the D10 by name and 768kHz compatible. I parked the H1 DAC/headamp on top for a bit of sibling rivalry, then plugged in our best planars, HifiMan's infamously inefficient Susvara. A 2 x XLR3 custom leash from Polish Forza Audioworks bridged the divide.

Next we see that rig with our residential Questyle CMA-800r monos below the iMac. Those usually perform balanced headphone drive coming off the Vinnie Rossi L2 Signature preamp's XLR outputs. Now the action was purely on the top deck. Everything below Artesanía Audio's upper glass shelves was out of commission except for the Vibex AC/DC filter on the lower right shelf. With one remote to control two COS, I sync'd up volume by hand, then grabbed the classy wand. -17.5 on their displays had Susvara in full flight. With +6 being end of line, that meant sufficient headroom for rarer albums whose expanded dynamic range means lower median levels. Those require more gain to match compressed recordings.

In the overlay, you see how the D10's display shows 'buffer on' at left, then incoming sample rate and bit depth, then signal lock with a musical note and active input in bold above. Whilst the remote offers four light intensities, display off is strangely absent. People who do their best work in the dark will hope for a firmware update. That should make it so that the display extinguishes fully minus perhaps the decimal point, then comes on for just a few seconds when any change is made by remote or hand.

Time to spin tunes and compare the D10's headphone chops to that of its dedicated headfi mate before going mano-i-mano with the D1 in DAC/preamp mode.