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Co-Operator
INSTALLATION
6)
The
clip
point
of
this
waveform
is
the absolute
maximum
peak
output
which
will
be produced by
the
Co-Operator
in
normal
operation.
7)
Adjust
the
Co-Operator's
L
OUTPUT ATTEN
control (or the
left
input attenuator
control
of
the
driven device)
until
the
peak
level
at
the
Co-Operator's output
matches
the
peak
overload
point
of
the
device being
driven.
For analog tape
recorders,
this
will typically
be
6dB
above
"Operating
Level"
(i.e.,
6dB
above
the
nominal
1%
total
harmonic
distortion
level).
For audio
power
amplifiers,
this
will typically
be
at
the
point clipping
begins.
For
USA-standard
telephone
lines,
this
will typically
be
at
+17dBu
into the line
(through
a
repeat
coil
supplied
by
the
telephone
company).
NOTE:
Place a
270-ohm ±5%,
'A-watt
carbon
film
resistor
(240-ohm
for
units serial
numbered below
1306000,
which have
93-ohm
output
impedance)
in series
with each
leg
of
the
Co-Operator's balanced
out-
put
to
ensure
that
the
phone
line
is
driven
by
a
true
600-ohm
source
impedance.
The +17dBu
must be measured on
the
phone
line
side
of
the
resistors.
You may
have
to
determine
the
peak
overload
level
by
experimentation,
or
by
referring
to
the
specifications
provided
by
the
manufacturer of
the driven
equipment
(especially
with broadcast
transmitters
and
digital
audio
encoders). This
is
particularly
important
if
the driven
equipment
employs a
sharp
cut-off
low-pass
filter
after
its
input,
since
such a
filter
will
overshoot
and
ring,
and
may
increase the
peak
level
applied
to
the
device
by
several
dB.
8)
Adjust
the
Co-Operator's
L
meter cal
control
until
the
L peak output level
meter's red
+3 segment
just
lights.
The L
PEAK OUTPUT LEVEL
meter
is
now
calibrated to the
driven equip-
ment.
When
the
red
+3
segment
lights,
the
overload point of the driven
equipment
has
been
reached.
9)
Repeat
steps 3
through
8
for the
right
channel.
Use
the
Co-Operator's
right
channel
terminals, controls,
and
meters
in
place of the
left
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