Time is of the Essence
In any digital audio system, the rate at which digital data is transmitted and received is of the utmost importance. Specifically, all devices in the digital signal path must be synchronized in order to provide a coherent presentation. Therefore, for the ultimate experience in clarity, transparency, focused imaging, and natural realism, your system’s digital source, DAC, and any other upsamplers or converters should all receive the same synchronized clock signal from an ultra precise and stable source.
The Aurender MC20 is both a Master Clock and Word Clock generator that is inspired, developed, and designed to deliver an exceptionally high level of digital audio realism from a connected music server and/or D/A converter. Thanks to the MC20’s superior timekeeping, jitter is reduced to infinitesimal levels resulting in the ultimate timbral purity and rock-steady placement of instruments within your system’s soundstage.
At the heart of the MC20 is a rubidium module that generates a 10MHz master clock reference signal. A rubidium clock is employed for its superior accuracy and stability in both the long and short term for ultra-low jitter. Additionally, MC20 contains two discrete OCXO word clock modules for generating the frequencies 44.1 kHz and 48 kHz. MC20 will independently and simultaneously supply the four 10MHz master clock outputs and four Word Clock outputs ( 2 at 44.1 kHz and 2 at 48 kHz ) for unprecedented versatility with a wide variety of Aurender and third party equipment.
Therefore, the MC20 can be used in the following scenarios:
1. Simultaneously supply a 10MHz master clock reference signal to source devices such as Aurender music servers, DAC's, and even separate word clocks with 10MHz master clock reference input.
2. Supply a 10MHz master clock to source devices such as an Aurender Music Server and word clock to DAC
3. Supply word clock to the source device and DAC
Rubidium Clock Module
The rubidium clock module employed in the MC20 is an exceptionally stable and accurate design that establishes a new low level of phase noise and jitter. Its flawless performance delivers a new level of vivid clarity with a three-dimensional width, depth, and height to the sound field it creates. The reduction of jitter and phase noise removes any trace of “digital glare,” and instead provides an analog-style warmth and naturalism to any digital audio source.
Rubidium modules are high-precision devices, and they are extremely delicate instruments. Consequently, Aurender engineers have designed a unique shock-mounted housing system to secure the module and isolate from vibrations both within the chassis and in the surrounding environment. To ensure the rubidium module can be safely transported, it arrives in its own foam case within the MC20’s master carton. Upon unpacking, the module will need to be installed by the user and locked into its dedicated chamber before use.
Oven Controlled Crystal Oscillator ( OCXO ) for Long Term Jitter Reduction
While the rubidium module takes care of MC20’s 10 MHz master clock generator signal, Aurender’s hallmark OCXO modules control individual word clock output. OCXOs are among the most accurate and stable clocks in use today. The OCXO modules deployed by Aurender’s engineers are orders of magnitude more accurate and stable than commonly used ordinary crystal oscillators usually found in computers. Temperature changes can cause crystal oscillations to fluctuate and induce jitter in the digital audio signal. Moreover, ordinary crystals are much less stable and lose accuracy over time. In OCXO clocks, a very stable high grade crystal oscillator is enclosed in a temperature-controlled compartment and kept at a constant temperature to mitigate jitter.
Connectivity - 10MHz Sine Wave Clock Outputs
A 10MHz master clock signal works as a reference signal which informs Aurender’s OCXO clock for greater accuracy and stability over both the short and long term. Since Aurender’s clock input has an impedance of 75Ω, connect the MC20’s 75Ω impedance 10MHz Master Clock to the clock input terminal on the Aurender server. By both measurement and listening tests the 10MHz output of the rubidium clock delivers higher performance than other methods. It is highly recommended!
If the DAC allows, it is recommended to use a 10MHz Master Clock. Otherwise, use the individualized word clock outputs. Choose the 75Ω or 50Ω outputs depending on the DAC’s input impedance. In order to avoid signal loss and / or jitter, it is important to match cable impedance.
In a scenario where the DAC has a word clock inputs, you can connect the 10MHz Master Clock output to your Aurender and simultaneously a Word Clock output to the DAC. Connect the SPDIF BNC output of your source to MC20 for automatic frequency synchronization depending on whether you are playing a 44.1 or 48 kHz base file.
Connectivity & Compatibility with Associated Components
MC20 can be used with a wide range of associated high-end brands of DACs and music servers. Current Aurender models supporting MC20 are N20, W20SE and N30/N30SA which all have a 75Ω clock input.
For interfacing with an Aurender, or another manufacturers’ components, two pairs each of 75Ω and 50Ω SPDIF cables are supplied. Please refer to the owner’s manual of any equipment that will receive clock input from MC20 to determine which impedance cable should be used.
|SPDIF Sync Input||Coaxial BNC, 75Ω ( BNC 75Ω )|
Rubidium Master Clock: 10MHz 2 each ( 75Ω ), 2 each ( 50Ω ), 0.7Vrms ( ±10% )
Word Clock: CH. A 2 each (75Ω), CH. B 2 each (75Ω)
USB ( Reserved for future use )
LED Indicators / Button
LED Indicators: Clock LED, Sync LED, Multiplier LED 10 each ( Channel )
Phase Noise ( Rubidium )
< -130dBc / Hz ( 10 Hz )
Freq. Short-term Stability
<2 ×10⁻¹¹ ( 1 s )
Phase Noise ( OCXO )
< -90dB/Hz ( 1Hz )
Freq. Stability ( OCXO )
<5 x 10⁻¹⁰
Size ( W x H x D )
16.9" x 4.2" x 14.6" ( unit only ), 5.0" height with foot
110V / 220V
Standby: 5.7W / Power On: Start Warm-up ( 160 W ), State Lock ( 58W )