Other devices — SOtM sCLK-OCX10

The sCLK-OCX10 is a master clock generator from SOtM, designed as an analogue-only device that brings recording-studio clock precision to a home audio streaming system. SOtM calls the clock signal the heart of a digital audio product, and the sCLK-OCX10 applies ten years of the company's work on clocking to this single component.

Key specs that matter

The output frequency is 10.000MHz, produced as a pure analogue sine wave instead of the square-wave digital clock signal used by most rival master clocks. Output level is 13dBm (2.825Vp-p at 50 ohms), plus or minus 2dBm. There are four isolated outputs on 50 ohm BNC connectors as standard, with 75 ohm versions available as an option, and on request the impedance can even be specified separately for each output of the same unit. Typical phase noise is -140dB/Hz at 10Hz and -165dB/Hz from 1kHz through 100kHz. Temperature stability is plus or minus 2E-9 across 0 to 50 degrees Celsius, referenced to 25 degrees. The unit runs from a 12V DC input, and a single LED indicator shows that it is operating.

Engineering and use context

SOtM chose the sinusoidal output because a sine wave carries significantly less noise than a conventional digital square wave. The design is entirely analogue, and each of the four outputs is isolated from the others so that one clock can drive several digital devices in the same system at once. The option of mixing 50 and 75 ohm outputs in one chassis lets the clock match the input impedance of different products without adapters.

Pairing

The sCLK-OCX10 connects to any device fitted with a BNC master clock input. Within SOtM's own range, a 10MHz master clock input can be added as an option to models equipped with the sCLK-EX internal clock, such as the sMS-1000SQ, sMS-200ultra and tX-USBultra, and the four outputs can then feed several of these units at the same time. SOtM's sNH-10G network switch, which also accepts the sCLK-EX module, completes a streaming system that uses this master clock.