Aurender MC20 Reference Master Clock & Word Clock Generator

The Aurender MC20 is Aurender's flagship reference master clock and word clock generator, combining a rubidium 10MHz master clock with two discrete OCXO word-clock generators. It can simultaneously provide four 10MHz master-clock outputs and four word-clock outputs, allowing an Aurender music server, compatible DAC and other digital components to operate from a highly stable timing reference. Aurender Music

Unlike the MC10, the MC20 adds dedicated 44.1kHz- and 48kHz-based word-clock generation, making it suitable for DACs and digital components that do not accept a direct 10MHz reference input.

Rubidium 10MHz Master Clock

The MC20's primary timing reference is a rubidium 10MHz clock module selected for extremely low phase noise and high short- and long-term stability.

Aurender specifies rubidium phase noise of:

• < -130 dBc/Hz at 10Hz
• < -140 dBc/Hz at 100Hz

Short-term frequency stability is specified at <2 × 10⁻¹¹ at 1 second, <1 × 10⁻¹¹ at 10 seconds and <2 × 10⁻¹² at 100 seconds. Aurender Music

Four 10MHz Master Clock Outputs

The MC20 provides four simultaneous 10MHz outputs:

2 × 75Ω BNC
2 × 50Ω BNC

Output level is 0.7Vrms ±10%.

Having both 50Ω and 75Ω connections allows the MC20 to interface correctly with compatible digital components using either clock-input impedance. The output, receiving component and clock cable should use matching impedance. Aurender Music

Dual Discrete OCXO Word Clocks

In addition to the rubidium master clock, the MC20 contains two independent OCXO — Oven-Controlled Crystal Oscillator — word-clock generators.

One channel can operate from the 44.1kHz frequency family while the second operates from the 48kHz family, with selectable multiples for higher sample rates. This allows the MC20 to synchronize DACs and other digital components that accept conventional word clock rather than 10MHz master clock. Aurender Music

The MC20 provides:

Word Clock Channel A — 2 × 75Ω BNC outputs
Word Clock Channel B — 2 × 75Ω BNC outputs

All four word-clock outputs can operate simultaneously with the four 10MHz master-clock outputs.

SPDIF Automatic Word Clock Sync

A dedicated 75Ω BNC SPDIF Sync input allows the MC20 to detect the sample rate of the incoming digital signal and automatically adjust its word-clock output to correspond with the content being played.

This eliminates the need to manually change the word-clock frequency as playback moves between different sample-rate families. Aurender Music

MC20 with Aurender Music Servers

Aurender specifically documents the MC20 for clock-enabled servers including the N20, N30/N30SA and W20/W20SE.

For these products, Aurender recommends using the MC20's 75Ω 10MHz master-clock output. The external 10MHz signal acts as the reference for the Aurender's internal clock. Aurender

For the highest clocking effectiveness, Aurender recommends using S/PDIF or AES/EBU between the Aurender transport and DAC. Because asynchronous USB places timing control on the DAC side, an external clock connected to the Aurender does not influence the USB Audio signal path in the same manner. Aurender

Aurender MC20 Technical Specifications

These are Aurender's current published MC20 specifications. Aurender Music

MC20 vs. MC10

The distinction between Aurender's two reference clocks is important.

The MC10 is focused on 10MHz rubidium master-clock generation. The MC20 adds two discrete OCXO word-clock generators, four 75Ω word-clock outputs and SPDIF automatic synchronization.

That makes the MC20 the appropriate choice when the system requires both 10MHz reference clocking and conventional 44.1/48kHz-family word clock—particularly sophisticated digital systems involving multiple clocked components.

Reference Digital Systems with dCS

The MC20 is particularly interesting for dCS systems because its separate word-clock architecture can accommodate DACs requiring sample-rate-related word-clock signals. Aurender's own MC20 documentation includes a connection example using a dCS Vivaldi DAC, including automatic switching between the 44.1kHz and 48kHz word-clock groups. Aurender

This gives The Grid a strong opportunity to sell the MC20 as part of a complete reference digital front end rather than as an isolated accessory.

Aurender MC20 at The Grid HiFi

The Aurender MC20 is intended for reference digital systems where the music server, DAC and clock architecture are engineered together. Its combination of rubidium 10MHz master clock, dual OCXO word clocks, 50Ω and 75Ω outputs, and automatic SPDIF synchronization gives it substantially broader system integration capability than a conventional external clock.

The Grid HiFi can configure the MC20 with Aurender music servers, dCS and other reference DAC systems, appropriate 50Ω/75Ω clock cabling, network architecture and digital connections.

Considering the MC20? Call The Grid HiFi at (713) 218-8120 and we'll design the complete digital front end around it.