USER GUIDE
PRO SERIES AUDIO ISOLATOR MODEL PC-2XR
The
PRO series audio ground isolation interfaces are designed for use in the finest professional sound systems.
They use the same Jensen transformers installed in tens of thousands of recording studios, broadcast facilities, and sound
reinforcement venues worldwide. Jensen audio transformers are industry benchmarks for sonic transparency because of
their extremely wide bandwidth, low harmonic distortion, and extremely low phase distortion.
Model PC-2XR is a two channel audio ground isolator designed to convert pro to consumer levels while solving the
following problems, which generally reveal themselves
only
when pieces of equipment are interconnected in a system:
!
Poor noise rejection by the equipments existing balanced input
. Most electronic or actively balanced input
circuits have high noise rejection or CMRR
only
when driven by laboratory equipment. The CMRR of these circuits
is exquisitely dependent on precision matching of impedances in the driving source equipment.
The transformers used
in the PC-2XR exhibit very high CMRR when driven by real-world balanced sources, and even unbalanced sources,
effectively eliminating noise due to voltage differences between equipment grounds.
!
Noise due to improper shield pin wiring inside the equipment
. Sometimes called the pin 1 problem, this
design defect effectively makes the equipments shield connection a signal input. Noisy ground currents, which
normally flow in the cable shield, then inject hum, buzz, and other noises into the signal path. This insidious defect,
which can exist at equipment inputs or outputs, can frustrate attempts to troubleshoot system noise problems because
its symptoms are so confusing.
The PC-2XR, via its built-in grounding option switches, can eliminate this problem by
interrupting or re-routing shield current flow.
!
Noise due to the equipments susceptibility to RF interference
. Most electronic or actively balanced inputs
will exhibit symptoms ranging from subtle audio quality degradation (fuzzy or grainy distortion) to outright
demodulation (heard as voices, music, or other noises in silent channels) when RF fields from broadcast or other
transmitters are present.
The transformers used in the PC-2XR inherently attenuate signals above about 100 kHz,
effectively eliminating RF interference. In addition, built-in resistor-capacitor networks help to control standing waves
which can make RF pick-up by cables especially severe
.
Model PC-2XR Application Guidelines
Source Impedance Range (
output
impedance of device
driving
the
input) . . . . . . . . . . . . . . . 0
!
to 5 k
!
Load Impedance Range (
input
impedance of device
loading
the
output) . . . . . . . . . . . . . 10 k
!
to 10 M
!
Maximum Recommended Input Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +29 dBu = 22 V RMS at 50 Hz
+26 dBu = 15 V RMS at 30 Hz
+21 dBu = 9 V RMS at 20 Hz
Signal Voltage Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 dB
The
PI- series, which is available with various connector options, may be driven by either balanced or
unbalanced outputs and may be used to drive either balanced or unbalanced inputs. When phase (polarity) inversion is
desired in any application, simply reverse connections at the
input.
Cables at the
PC-2XR outputs should be less than 10 feet long !!
The added capacitance of longer cables can degrade high frequency bandwidth and transient response. Keep the cables
as short as possible, although performance is not improved for lengths under 8 inches. Do
not
route the output cables to
a patchbay where additional cable lengths will be used to route signals to device inputs. The length limitation applies to
all
cable between each
PC-2XR output and the device input which it drives.
PROPER INSTALLATION IS ESSENTIAL TO ACHIEVE OPTIMUM AUDIO PERFORMANCE
PLEASE READ THIS GUIDE CAREFULLY !