Wiring The Interfaces & General Recommendations For Interface Wirings & Cables - Mutec MC-3+ Smart Clock USB Operating Manual

Installation
Wiring the Interfaces
Word Clock
To allow for the synchronization of signals, the interfaces of all devices involved must be properly connected to each other to
ensure a logical signal flow. Always be sure to connect the Word Clock output(s) to the corresponding input(s) of the device(s)
you wish to synchronize. Cable lengths should be kept as short as possible to minimize signal losses and/or interferences!
For the transmission of Word Clock signals, unsymmetrical cables with a impedance of 75 Ω and BNC connectors on both ends
are used. Typically, such cables are marked with »RG-59U, RG59B/U«.
Additionally, make sure that the Word Clock input(s) incorporate a 75 Ω terminating resistor! Most Word Clock inputs allow
for enabling/disabling the termination with a so-called »termination-switch«, which may be located on the outside or inside of
the device. For devices which have no termination of the Word Clock input, e.g. RME Hammerfall with Word Clock i/o, Alesis
BRC or M-Audio ProFire Light bridge, you can use an additional BNC-T piece to terminate the input. Plug the T piece with its
center connector into the input of the receiving device. Then, connect the cable coming from the Word Clock output to one of
the lateral connectors, and the other connector of the BNC-T piece to a 75 Ω resistor forming the BNC termination.
Basically, you should avoid »looping through« Word Clock leads by means of passive BNC-T pieces to preserve the signal qual-
ity, as level drops will be the result. If there is no other way to wire your set-up, please make sure that all Word Clock inputs
(except for the last device in the chain) have their terminations disabled! In a serial Word Clock chain only the last clock input
should have a termination! Never connect more than three devices in series to one output!
AES/EBU
Connect the AES/EBU interfaces with the help of balanced electrical cables equipped with XLR connectors on both ends. The speci-
fications stipulate a specific cable impedance of 110 Ω (ask your retailer for a confirmation of this value when buying the cables).
S/P-DIF
Two coaxial S/P-DIF interfaces are available, one based on standard RCA, the other one based on BNC connectors. Connect
these interfaces with help of unbalanced electrical cables equipped with RCA respectively BNC connectors on both ends. The
specifications stipulate a specific cable impedance of 75 Ω for both. Ask your retailer for a confirmation of this value when
buying the cables.
Connect the optical S/P-DIF interface with the help of Toshiba TOSLINK™ compliant optical fiber cables. You can use both
plastic and glass fiber-based cables.
General Recommendations for Interface Wirings & Cables
Word Clock
If a cable with a different impedance than 75 Ω is used, a dramatic deterioration of the signal quality is the result! In this case,
the sound quality and synchronization of all devices involved can be impaired.
It is imperative that the lengths of all cables connected are largely the same to ensure that all devices will be synchronized in
phase (exception: cable tolerances).
We recommend using high-grade cables with a good shielding. A length of max. 10 meters (approx. 30 feets) should not be
exceeded!
AES/EBU & S/P-DIF Interconnections
When working with XLR-based AES3/-11 or RCA-based S/P-DIF audio signals at high sampling rates , well-shielded electrical
cables are mandatory to avoid increased radiation! Standard cables are normally useable for sampling rates up to 50.0kHz.
When interconnecting the optical S/P-DIF interfaces with plastic fiber cables, lengths of 10 meters should not be exceeded,
to ensure reliable transmission of your digital audio signals. Glass fiber cables may transfer data reliably even over greater
distances while keeping the signal's performance on a much higher level than plastic fibre cables can do during transmission!
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