This review page is supported in part by the sponsors whose ad banners are displayed below

The compact SOtM devices arrived professionally foam-ensconced each in its own custom shipping box and turned out to be surprisingly light in weight but classy of finish. Their tops came off easily because what seemed like a solid black longitudinal extrusion at first is actually a two-part clamshell. Simply remove the upper bolts and presto. The super clock board slips into the top half facing down on the main board..

Optional sCLK-2224 super clock board

The sCLK-2224 adds the two previously mentioned Sunny precision clocks each with its own circuit as shown above.

Here is another view of the dX-USB HD main board with the popular super-stable XMOS chip...

... and a closeup of the clock board's premium Rifa capacitor...

... and finally a closer view of the circuit preceding one of the precision clocks.

The battery supply and USB bridge connect via a short white-mesh power umbilical. The supply itself charges its twin batteries via an included SMPS wart from the wall. The obvious multi-LED displays on either box confirm operational status and incoming sample rate. The 'in-between' values of 32kHz, 88.2kHz and 176.4kHz are indicated with two LEDs each to make do with just four lights.

Upon cabling up, my iMac with OSX 10.8.2 immediately recognized the device as SOtM USB 2.0 Audio Out without having to install the driver supplied on CD/ROM. Because the batteries arrived depleted, there wouldn't be instant gratification but some charging first. Afterwards neither Metrum Hex nor Eximus DP1 would lock on coax or AES/EBU even though Audirvana and PureMusic both streamed uninterrupted and the SOtM acknowledged receipt at the proper sampling rates. My SOtM contact May Park swiftly dispatched a replacement which completed the Incheon/Korea, Almaty/Kazakhstan, Warsaw/Poland, Köln/Germany to Meyrin/Switzerland trip in all of two days. That one worked fine.