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Co-Operator
INSTALLATION
Grounding
Very
often,
grounding
is
approached
in
a
"hit
or miss" manner.
But
with
care
it
is
possible
to
wire an audio
studio so
that
it
is
free
from ground
loops
(which induce
hum
and can
cause
oscillation)
and
provides
maximum
protection
from
power
faults.
•
All
units in the
system
must have
balanced
inputs.
In
a
modem
system with
low
output
impedances and
high
input
impedances,
a
balanced
input
will
provide
common-mode
rejection
and
prevent
ground
loops
—
regardless
of
whether
is
driven
from
a
balanced or unbalanced
source.
(The Co-Operator
has balanced
inputs.)
•
All
equipment
circuit
grounds
must
be connected
to
each
other,
all
equipment
chassis
grounds
must
be
connected
together.
•
Cable
shields
must
be
connected
at
one end
only
—
preferably the
source
(output) end.
Power:
•
Ground
the
Co-Operator
chassis
through
the
third
wire
in the
power
cord.
Proper grounding
techniques never leave
equipment
chassis
unconnected
to
power/earth ground.
A
proper
power
ground
is
essential
to
safe operation.
Lifting
a
chassis
from power ground
is
a
safety hazard.
If
there
is
a
power
fault to
the chassis,
death could
result!
Circuit:
To
maintain
the
same
potential in
all
equipment,
the
circuit
(audio)
grounds
must be
connected
together:
•
In
a
simple one-studio
system, the
connection through
power
ground
(via
the
power
cord's
third
wire)
will
suffice,
Connect
the
Co-Operator's
circuit
ground
(
^
)
terminal
to
its
chassis
ground
)
terminal.
Also connect
the
circuit
and
chassis
grounds of
other
equipment.
•
In larger systems,
it
is
common
to establish
an
isolated
circuit
ground system
that
is
insulated
from
the
power
ground
except
at
one
point (usually
the studio
power
distribution panel). In
this
case,
disconnect the Co-Operator's
circuit
ground
(
^
)
terminal
from
its
chassis
ground
)
terminal,
then
connect
the
Co-Operator's
circuit
ground
(
^
)
terminal
to
the isolated
circuit
ground
system.
Audio
Output:
•
Use
two-conductor
shielded cable
(Belden 8451, or
equivalent).
•
At
the
Co-Operator's output
(and
at
the
output
of
other
equipment
in
the
system),
connect
the cable's
shield
to
the
^
terminal for
that
channel.
Connect
the
red
(or white)
wire
to
the
channel's HI
terminal,
and
the
black
wire
to the
channel's
LO
terminal.
•
To
interface units
with unbalanced
inputs
in
a professional
system,
install
a balancing transformer (Jensen JE-
11 P-1,
or
equivalent) to
prevent
ground
loops.
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