The SOtM sCLK-OCX10ultra is a next-generation high-end 10MHz Master Clock Generator, engineered to provide an exceptionally pure and stable timing reference for digital audio systems. Featuring 10 independently isolated BNC outputs, ultra-low phase noise and outstanding ±5ppb temperature stability, it can synchronize an entire digital system from a single precision clock.
Its proprietary 10MHz analog sine-wave output helps deliver greater spatial stability, finer detail, deeper musical texture and a more natural, refined presentation.
One ultra-precise clock. Ten isolated outputs. One perfectly synchronized digital audio system.
The SOtM sCLK-OCX10ultra is a next-generation high-end 10MHz Master Clock Generator, developed to provide an exceptionally stable reference clock for compatible digital audio components.
Building upon the technology of the acclaimed original sCLK-OCX10, the new Ultra introduces a significantly expanded output architecture, further refined oscillator performance and a sophisticated approach to electrical isolation.
With 10 independently isolated 10MHz BNC outputs, the sCLK-OCX10ultra allows multiple compatible digital audio devices to receive their reference signal from one dedicated precision clock.
Developed for sophisticated high-end systems, it combines an ultra-low-phase-noise oscillator, proprietary analogue sine-wave output circuitry and carefully designed regulation within a substantial, dedicated chassis.
Its purpose is to provide a common timing reference for compatible equipment while supporting SOtM’s continuing pursuit of greater precision in digital audio reproduction.
A New Generation of SOtM Master Clock Technology
In digital audio, accurate timing is essential to the operation of converters, digital interfaces and other clock-dependent electronic systems.
Different digital components employ their own internal clock architectures to organise sampling, data transfer and signal conversion.
In systems designed to accept an external reference, a precision master clock can provide a shared frequency standard to multiple connected devices.
SOtM developed the sCLK-OCX10ultra to perform this specialised role with exceptional attention to oscillator stability, phase noise and output isolation.
The new design takes the company’s original sCLK-OCX10 concept further by increasing the available reference clock connections from four to ten and introducing refinements to the internal oscillator system.
The result is a master clock intended for complex reference systems in which several compatible components can benefit from access to the same 10MHz reference frequency.
Ultra-Precise 10MHz Reference Clock
At the centre of the sCLK-OCX10ultra is a high-precision oscillator designed to generate a 10.000MHz reference signal.
SOtM employs its proprietary analogue output circuitry to produce a sinusoidal 10MHz clock signal rather than relying on a conventional square-wave output design.
The clock is intended for audio components that specifically support an external 10MHz reference input.
Correctly implemented, an external reference may be used by the receiving device’s own clock-control system to synchronise its internal timing architecture.
Important: A 10MHz master clock is not a replacement for every internal audio clock, and connecting an external reference does not mean that every component uses a single identical audio sampling clock.
The actual relationship between external reference timing and digital audio conversion depends on the design of each receiving device.
10 Independently Isolated BNC Clock Outputs
One of the most important features of the SOtM sCLK-OCX10ultra is its extensive output architecture.
The unit provides 10 independently isolated BNC clock outputs, making it possible to distribute the 10MHz reference signal to multiple compatible components.
Each output incorporates a dedicated isolation arrangement designed to reduce unwanted electrical interaction between connected devices.
This approach is particularly useful in complex digital audio systems where network infrastructure, USB interfaces and other compatible components may require their own external reference inputs.
By providing ten outputs within a single chassis, the sCLK-OCX10ultra reduces the need for multiple separate 10MHz clock generators.
Its isolation architecture is a central feature of the design and reflects SOtM’s attention to electrical noise management throughout a complete digital system.
Advanced Oscillator with Ultra-Low Phase Noise
Phase noise is an important measure of oscillator quality, describing unwanted short-term frequency fluctuations around the intended carrier frequency.
For a precision 10MHz clock, phase-noise behaviour can be evaluated at different frequency offsets from the reference carrier.
SOtM specifies significant improvements in the Ultra’s oscillator performance compared with its predecessor.
In particular, the manufacturer reports approximately 5dB lower phase noise at the 10Hz offset.
The published typical phase-noise characteristics of the internal oscillator are:
Frequency Offset
Typical Internal Oscillator Phase Noise
10Hz
-145 dBc/Hz
100Hz
-160 dBc/Hz
1kHz
-165 dBc/Hz
10kHz
-168 dBc/Hz
100kHz
-170 dBc/Hz
These values describe the typical internal oscillator performance published by SOtM. They are not a substitute for complete output-level phase-noise measurements of the finished clock distribution system.
Improved Phase Noise Compared with sCLK-OCX10
The original sCLK-OCX10 established SOtM’s dedicated high-end reference clock approach with four isolated outputs.
The new Ultra expands this concept with ten isolated connections and an oscillator offering improved phase noise at several published offsets.
At the 10Hz offset, SOtM specifies -145 dBc/Hz for the sCLK-OCX10ultra compared with -140 dBc/Hz for the original model.
This represents a 5dB improvement in the manufacturer’s published typical figure.
The new oscillator also reaches -170 dBc/Hz at the 100kHz offset.
The earlier model, however, retains a better published numerical temperature-stability specification of ±2ppb compared with ±5ppb for the Ultra.
The Ultra should therefore be understood as a more extensively equipped clock with improvements in selected performance areas, rather than a device with a superior numerical specification in every category.
Pure 10MHz Analogue Sine-Wave Signal
The sCLK-OCX10ultra employs SOtM’s specialised analogue circuitry to generate its external 10MHz sine-wave reference.
The manufacturer describes this approach as an alternative to clock products that supply a digital square-wave output.
The resulting signal is intended to serve as a clean, stable reference for compatible audio equipment.
The exact output waveform requirements of the receiving component must be confirmed before connection.
A device designed for a different reference frequency or incompatible signal level must not be connected simply because it uses a BNC socket.
Temperature Stability of ±5ppb
Oscillator frequency can vary with temperature, making thermal stability an important characteristic of a precision clock.
SOtM specifies a temperature stability of ±5 parts per billion (ppb) over the internal oscillator’s stated 0°C to +50°C temperature range.
This specification describes the oscillator’s frequency stability as the temperature changes within the stated range.
The recommended operating temperature of the complete sCLK-OCX10ultra component is +10°C to +30°C.
For reliable performance, position the unit in a well-ventilated location and avoid placing it directly above equipment that produces substantial heat.
50Ω and Optional 75Ω BNC Connections
The standard sCLK-OCX10ultra is equipped with ten 50-ohm BNC clock output connections.
SOtM also offers an optional 75-ohm BNC configuration.
These options allow the master clock to be matched with compatible equipment requiring the appropriate transmission-line impedance.
The correct impedance should be selected according to the receiving component’s specifications.
For example, many professional 10MHz reference systems employ 50-ohm connections, while other equipment may require 75-ohm clock inputs.
A 75-ohm digital S/PDIF input is not automatically a compatible 75-ohm 10MHz reference input.
Similarly, an ordinary word-clock input designed for audio sampling-related clock frequencies must not be assumed to accept a 10MHz signal.
Always use the appropriate BNC cable and verify frequency, waveform, signal level, connector impedance and input configuration before making a connection.
Clocking a Complete SOtM Digital Audio System
The sCLK-OCX10ultra has been designed for sophisticated installations using multiple devices equipped with external 10MHz reference inputs.
Potential applications include compatible network switches, digital interfaces and specialised audio clock systems.
Within the SOtM ecosystem, compatible versions of the sNH-10G network switch and other clock-capable products may form part of a synchronised reference system.
Compatibility depends on the exact product version and the availability of an external 10MHz input.
The SOtM sMS-2000 Network Streamer & Music Server is another relevant system-building product, because certain configurations incorporate dedicated clock-related hardware and 10MHz reference input capability.
Check the installed clock modules and connection requirements before specifying an external master clock.
Compatible clock-enabled configurations may be used with an external 10MHz master clock.
A shared reference can form part of a complete SOtM digital audio infrastructure, alongside appropriate power supplies, Ethernet cables and digital transports.
The sCLK-OCX10ultra does not replace the switch’s Ethernet data functions. It serves only as an external timing reference for supported clock circuitry.
Designed for Reference-Level Digital Systems
SOtM’s development philosophy recognises that digital audio performance depends on more than computing speed or the availability of high-resolution music files.
Power quality, electrical noise, data interfaces and clock architecture must work together within the system.
The sCLK-OCX10ultra is intended to address the precision-reference-clock element of this wider engineering approach.
By distributing an isolated 10MHz signal to compatible components, it provides a central reference around which a more elaborate digital installation can be designed.
The specific audible result depends on how each device uses the reference, the quality of its existing clock architecture and the complete listening system.
The Listening Philosophy
SOtM describes the sonic objective of the sCLK-OCX10ultra in terms of increased spatial stability, finer detail and a more natural sense of musical expression.
The manufacturer also emphasises the perceived weight and texture of the lower frequencies, together with greater differentiation between instruments.
These descriptions reflect the company’s subjective listening assessments and design intentions.
External clocking can influence the performance of compatible digital systems, but an audible improvement cannot be guaranteed in every installation.
Careful matching with the receiving equipment is essential.
Dedicated 12V DC Power Input
The sCLK-OCX10ultra requires an external 12V DC power supply with sufficient current capability.
The manufacturer specifies a maximum input current of 3A and a 5.5mm outer diameter / 2.1mm inner diameter DC power connector.
Its stated input voltage tolerance is -0.05V to +0.5V relative to the nominal 12V setting.
This relatively specific power requirement makes correct external power supply selection especially important.
A suitable supply must meet the voltage, current capacity, polarity and connector requirements of the unit.
Important Information About External Power Supplies
SOtM’s sPS-550 Power Supply offers a selectable 12V DC output and a corresponding published current capability of 6.6A.
However, the sCLK-OCX10ultra has a narrow stated input-voltage tolerance, and the sPS-550’s published voltage tolerance is wider.
Therefore, electrical compatibility must be explicitly confirmed by SOtM before combining the two products.
Do not assume compatibility solely because both devices specify a nominal 12V DC connection.
SOtM sCLK-OCX10ultra vs sCLK-OCX10
The original SOtM sCLK-OCX10 established the manufacturer’s first dedicated external 10MHz master clock platform.
The new sCLK-OCX10ultra represents the next stage in this development.
Specification
sCLK-OCX10
sCLK-OCX10ultra
Reference Frequency
10MHz
10MHz
Isolated Outputs
4
10
Phase Noise at 10Hz
-140 dBc/Hz
-145 dBc/Hz
Phase Noise at 100kHz
-165 dBc/Hz
-170 dBc/Hz
Temperature Stability
±2ppb
±5ppb
Power Input
12V DC
12V DC
Dimensions
106 × 48 × 245 mm
298 × 227 × 50 mm
The Ultra provides considerably more clock outputs and improved typical phase-noise figures at selected offsets, while the original model has a tighter published temperature-stability specification.
Typical -145 dBc/Hz internal oscillator phase noise at 10Hz offset
Typical -170 dBc/Hz internal oscillator phase noise at 100kHz offset
Approximately 5dB improvement at 10Hz offset over the original sCLK-OCX10
Proprietary analogue sine-wave output circuitry
Ultra-low-noise regulator design
±5ppb oscillator temperature stability over the stated temperature range
Dedicated 12V DC power input
Designed for distribution of a common reference to compatible digital audio components
Substantial dedicated chassis for reference-level installations
International Reviews & Recognition
The sCLK-OCX10ultra is a recently introduced generation of SOtM master clock technology.
At the time of this presentation, the official manufacturer page does not list a dedicated independent magazine review or award for the Ultra model.
Reviews and awards associated with the earlier sCLK-OCX10, sCLK-OCX10 SE or complete SOtM digital systems should not be presented as awards for the new sCLK-OCX10ultra.
±5ppb, specified oscillator temperature range 0°C to +50°C
DC Power Input
12V DC
Tolerance: -0.05V / +0.5V DC
Maximum current: 3A
DC Connector
5.5mm OD / 2.1mm ID Barrel Connector
User Interface
1 Operating Indicator LED
Operating Temperature
+10°C to +30°C
Storage Temperature
0°C to +40°C
Humidity
10% to 90%
Dimensions
298 × 227 × 50 mm
Weight
Approximately 1.7 kg
Frequently Asked Questions
What is the SOtM sCLK-OCX10ultra?
It is a high-end 10MHz master clock generator with ten independently isolated BNC reference outputs.
What is the difference between the original sCLK-OCX10 and the Ultra?
The Ultra provides ten instead of four isolated outputs and offers improved typical phase-noise performance at selected offsets. Its published temperature-stability specification differs from the original model.
What type of clock signal does it produce?
It produces a 10.000MHz analogue sine-wave reference clock signal.
How many devices can it connect?
It provides ten isolated clock output connections, allowing up to ten suitable reference-clock inputs to be served, subject to signal and impedance compatibility.
Can it be connected to any DAC?
No. The DAC must specifically support a compatible external 10MHz reference input.
Can I connect the clock to an S/PDIF BNC input?
No. A conventional S/PDIF digital audio input is not the same as a 10MHz reference clock input.
Does the Ultra support 75-ohm connections?
Yes. SOtM offers an optional 75-ohm BNC configuration in addition to the standard 50-ohm arrangement.
Is 50Ω or 75Ω better?
Neither is universally better. The correct choice depends on the receiving equipment’s required input impedance and the transmission system.
What is phase noise?
Phase noise describes unwanted short-term frequency or phase fluctuations around the nominal clock carrier. Lower values can indicate better oscillator performance under comparable measurement conditions.
Does the sCLK-OCX10ultra improve sound quality in every system?
No. The result depends on the receiving device’s clock implementation and the complete audio system.
Can it work with a SOtM sNH-10G switch?
Yes, when the particular sNH-10G configuration has a compatible external 10MHz reference-clock input and the correct BNC connection is used.
Can it be integrated with the sMS-2000?
Compatible configurations of the sMS-2000 can include specialist clock hardware suitable for integration with a 10MHz reference. The exact configuration must be verified before connection.
What power supply does it require?
The manufacturer specifies 12V DC with a maximum input current of 3A and a particular voltage tolerance.
Can it be powered by the SOtM sPS-550?
Do not assume automatic compatibility. The precise sPS-550 output voltage regulation, polarity and cable configuration must be confirmed against the Ultra’s stated requirements.
What are the dimensions?
The chassis measures 298 × 227 × 50 mm and weighs approximately 1.7 kg.
Why Choose the SOtM sCLK-OCX10ultra?
The SOtM sCLK-OCX10ultra 10MHz Master Clock Generator combines ten isolated reference outputs, refined low-phase-noise oscillator engineering and precision clock distribution in one dedicated component.
It provides an attractive foundation for sophisticated digital audio systems built around devices capable of accepting an external 10MHz reference.
One Precision Reference. Ten Isolated Outputs. A More Integrated Digital Audio System.
Availability and International Orders
Contact Chameleon Audio for current availability, 50Ω and 75Ω configurations, suitable BNC clock cables, power supply compatibility and personalised advice on integrating the sCLK-OCX10ultra into your high-end audio system.
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