Wheatstone IP-12 - Energizing

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IP-12/IP-16 / Dec 2014
WHEATNET-IP 88cb CONSOLE BLADE
the shield to a convenient ground connection at one end only – typically when
equipment is being connected in this fashion you choose to make your ground
connection consistently at either the source or the destination, using the same
grounding scheme wherever in the system such connections are made
• for an audio output from the BLADE, the same connections can be made as are
used for the inputs
• adapters are commercially available with RJ‑45 connectors on one end and the
appropriate audio connector type, such as RTS or XLR, on the other
• balanced to unbalanced adapters, also called baluns, are commercially available to
transform the unbalanced connection to a balanced connection – these are usually
active devices and will account for level differences as well as converting between
balanced and unbalanced connections
• For digital audio connections always use a good quality digital audio cable with a
characteristic impedance of 110 ohms.
The AES/EBU specication, with its broad impedance tolerance, allows for cables with impedances
from 88 ohms to 132 ohms – 110 ohms is ideal. Twisted pair cable should be shielded, and in the
case of multi‑pair cable, each pair should be individually shielded. Foil shielding is recommended for
permanent installations and foil shield plus overall braid should be used in applications where frequent
exing of the cable will occur. One cable pair is capable of carrying two channels of digital audio.
Generic “audio” cable such as Belden 8451 may be used for interconnecting AES3
digital audio devices but only for distances of less than about 25 feet. The actual
cable length that will work satisfactorily in an installation is primarily determined
by the error correction and jitter tolerance of the AES3 receiver device and the
cable used.
The impedance of most “analog” cables ranges from 40 ohms to 70 ohms and represents a large
impedance mismatch from the nominal 110 ohms required in the AES3 standard. Such mismatch
will result in signal reections, causing bit errors at the AES3 receiver. The higher capacitance of
generic analog cables also slows down the rise time of the digital data signals, impairing the ability
of the AES3 receiver to accurately detect digital signal transitions. This may result in increased jitter.
Energizing
There is no power switch. The AC line input voltage is permitted to be between 90
and 260VAC, 50 or 60Hz. Power consumption is under 100VA.
Aggressive AC input ltering is utilized at the AC input of the WheatNet‑IP; however,
it is always advisable to use external surge protection and/or an uninterruptible power
supply (UPS), especially where AC power quality is questionable, such as at a remote
transmitter site.
Power conditioning, surge suppression, and even power backup devices are wise
investments when using sensitive modern electronic devices that use an internal computer.
Use of a UPS (uninterruptible power supply) is a good idea and will protect the
WheatNet-IP from short duration power interruptions which may cause it to reboot.
During boot up, audio is interrupted for approximately 40 seconds.