Table of Contents
Advertisement
Appendix A:
We've told you, both earlier in this manual, and in
Introduction to Livewire; System Design Reference
& Primer, that Axia recommends balanced audio con-
nections when connecting analog source and destina-
tion gear to the inputs and outputs, respectively, of Axia
nodes. Not only do we recommend this for the usual
reasons, but because inter-channel crosstalk between the
left and right channels of unbalanced signals sharing the
same Cat. 5 cable is a possibility. As we've mentioned
before, we recommend converting between balanced
and unbalanced at the unbalanced device and then using
the standard Cat. 5 connection from there to the Axia
node.
There are a number of active balanced-to-unbalanced
and unbalanced-to-balanced adaptors commercially
available at a reasonable cost (see www.studiohub.com
for a pair of units that will easily plug and play with our
gear). We'll suggest one more time that this approach
is the way to go, and that using unbalanced cable runs
will compromise the performance of your state of the
art Axia audio network. However, if you are in a bind, or
otherwise determined to do so, here is how we recom-
mend connecting Axia nodes to unbalanced equipment:
Unbalanced Destinations
To feed audio to an unbalanced destination from the
8x8 Analog node you must use a separate cable for the
left and right signals, and you will need a shielded RJ-45
plug so you can terminate the shield of the audio cables.
RJ-45 Pin 1 will feed the Left signal with the signal com-
mon (e.g. cable shield) connected to the RJ-45 shield.
Pin 3 will feed the Right signal with the signal common
(e.g. cable shield) connected to the RJ-45 shield.
An external pad may be required if the destination
equipment's inputs cannot accept signals with peak lev-
els of +24 dBu.
Generally the unused output pin should not be tied to
Unbalanced Connections
the shield. Doing so will not harm the node, however do-
ing so will activate a feature that will increase the output
level by 6 dB, which is generally not desirable.
8
Feeding unbalanced device inputs from Axia 8x8
Unbalanced Sources
To feed an unbalanced signal from a source into the
inputs of the analog 8x8 node you must use a separate
cable for the left and right signals. We generally prefer
the method where the unbalanced signal is presented
across the differential balanced inputs of the node. The
handling of the shield will depend on the equipment and
grounding practices used.
If both pieces of equipment are grounded to a facility
grounding system then the shield may be left open at one
end (or both ends), as follows.
8
1
Axia node's analog inputs fed from an unbalanced
source where both pieces of equipment are tied to a
Version 1.2 July 2010
+
+
1
analog node outputs.
facility ground.
R
L
+
R
+
L
Advertisement
Table of Contents
