Installation - Phonic PCR2213 PLUS Manual Del Usuario

3.0 INSTALLATION

3.1 RACK MOUNTING
The Phonic PCR2213 Plus fits into standard rack, and takes one
unit height of space (1 3/4"). Additional 4" depth for the connectors
on the back panel is needed. Be sure that there is enough air space
around the unit for cooling and please do not place the PCR2213
Plus in contact to or directly on top of high temperature devices
such as power amplifiers etc. to avoid overheating.
3.2 CONNECTORS
The PCR2213 Plus has to be connected with XLR plugs. Although
the inputs and outputs are fully balanced, the active servo circuitry
can be wired with unbalanced sources and loads as well.
3.2.1 Impedance
Both of the inputs impedance are 20k Ohms and can be driven by
most sources. If a device's output requires a match load of 600
Ohms (mostly from output transformers), 600 Ohms resistor should
be tied across pin 2 and 3 on the input connectors. As standard,
the outputs of the PCR2213 Plus are electronically balanced and
have an output impedance lower than 100 Ohms. When driving
transformer coupled loads, it may be necessary to create a 600-
Ohm source impedance. For this purpose, install two 247 Ohms
resistors in series with pin 2 and 3.
3.2.2 Unbalanced/Balanced Connection
Most of the mistakes in audio installations are incorrect and defec-
tive audio connections. In order to perfectly complete your instal-
lation, please pay special attention to the following section unless
you are already familiar with balanced/unbalanced operation.

What is an unbalanced system?
You can find this system in most of home audio-video system. It
got one conductor to carry the signal, and the other conductor for
ground. Normally for lower level signal, the signal conductor is
shielded by the ground conductor.

What is a balanced system?
Balanced system transmits the signal via 2 conductors plus one
ground shielding conductor. The 2 signal conductors carry the
same signal but out of phase. For the balanced input stage, the
amplifier will boost the difference of the 2 signal conductors and
remove the identical part (known as common mode signal.) of the
2 signal conductors. Because of the real signal is carried by the
2 conductors out of phase, so it is perfectly carry to the input. At
the same time, the interference occurs during transmission will be
identical part (common mode), because the signal conductors are
run together, there is no chance they can be different, and all the
interference will be removed by the balanced input amplifier.

The difference in between 2 operations:
Because the common mode interference immunity of balanced
system, and at the same time, the ground conductor doesn't
need to carry any electrical current so that it means the ground
of the 2 connected units has identical ground level which is vital
to interference free system.
PCR2213
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Let's look back to unbalanced system, the signal electrical current
is from signal conductor to ground conductor, and that means the
ground level of 2 connected units are not identical. This means the
system is much more easier to be interfered with noise.
Running long cables is easy for balanced system but difficult for
unbalanced system, and lower noise is always characterized in
balanced system.
Because balanced system needs 2 conductors for signal and
1 conductor for ground, minimum 3 conductors are needed for
wiring balanced system. So dedicated system separates ground
and shield as 2 conductors.
Please read following section for proper wiring balanced and
unbalanced system:
3.2.3 The Correct Wiring for Balanced Operation
Always connect the main power with 3-prong plug. Make sure the
power system ground is properly done. Don't use ground insulator
plug adapter without properly connect the ground individually. This
is vital to a successful audio system connection. Always connect
the ground pin (PIN 1 in XLR) to the source unit, and disconnect
this pin at the destination unit. This connection topology is to avoid
grounding loop created by both connection of signal and power
ground. To utilize only the power ground, is because it always
has lower resistance and better distribution than signal ground. If
there is hum, a very possible cause is bad grounding connection
in the system. In case you can not find the cause, try to connect
the ground pin of the input connectors. If the hum is reduced or
eliminated, check your power grounding system. Special atten-
tion while distant equipment racks, and/or large quantity of power
amplifiers are used. Check the power ground between the racks
and power distribution strips with your electricity engineer. Do
make sure there is one and only one proper ground point in the
audio system (or connected video system.)
3.2.4 Unbalanced Operation
PCR2213 Plus is equipped with electronically balanced inputs and
outputs which also function unbalanced inputs and outputs. The
cross-feedback circuitry recognizes the connection of unbalanced
loads and compensates 6 dB level difference when one of the
signal is shorted to the ground.For connecting with unbalanced
source to the input of PCR2213 Plus, connect PIN 2 of XLR con-
nector to the source signal and the PIN 1 and 3 of XLR connector
of PCR2213 Plus to the source ground. For connected with unbal-
anced load to PCR2213 Plus, there are 2 possible wiring methods:
(1): Connect PIN 2 of XLR connector to the load input, and connect
PIN 1 of XLR connector to the load ground. (2): Connect PIN 2 of
XLR connector to the load input, and connect PIN 1 and 3 of XLR
connector to the load ground.
3.2.5 Balanced Operation
The electrically balanced connections have the benefit of Common
Mode Rejection which eliminates externally induced interference,
such as mains hum etc. Balancing is especially useful when long
cable runs are used between pieces of equipment. For connecting
with balanced source to the input of PCR 2213, connect PIN 2 of
XLR connector to the source signal Hot(+), the PIN 3 to the source
signal Cold(-) and the PIN 1 to the source Ground.
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