ARP 2600 - Gain Adjustment for VCF; Frequency Calibration Steps for VCF

112
3.
Insert
dummy plugs
into
the
KBD
CV
input jacks on
VCO-2
and on
the Filter.
4. Set VCO-2
frequency
at 1 KHz;-set the Filter frequency
at
1KHz.
5.
Advance
the Filter
RESONANCE lo maximum.
6.
Raise
both
of
the Mixer
input attenuators halfway. Raise
the
Speaker Volume
controls
to
a
comfortable
level.
7.
ADJUST THE "FREQ
CALIBRATE"
TRIMMER
ON THE
VCF
UNTIL
THE
VCF
AND VCO-2 OUTPUTS ZERO-
BEAT.
6.124
1V/OCTAVE
CALIBRATION.
1
.
Begin
with
ail control sliders
at
minimum, i.e. down
or left.
2.
With
a patch cord, connect
the
VCO-2
SINE
output
to the
second
MIXER
input, interrupting the
VCA connection
to
that
input.
3.
Set
VCO-2 and the Filter
both to about 500Hz.
4.
Advance
the Filter RESONANCE
to
maximum.
5.
Open the Mixer input attenuators about halfway and
set
the
Speaker Volume controls
to
a comfortable level.
6.
Holding
down the lowest note on the keyboard, tune the
V
Filter
to unison
with
VCO-2
by
zero-beating them.
7.
Holding
down the
C
three
octaves above the lowest
note
on
the
keyboard,
ZERO-BEAT THE
FILTER AND VCO-2
BY
ADJUSTING THE
"1V/OCT" TRIMMER ON THE
FILTER.
8.
Repeat
steps 6
and 7 as
needed
for
precise tracking.
6.13
ADJUSTING THE
VOLTAGE-CONTROLLED
AMPLIFIER.
Here we are concerned
with high-frequency and control-signal
rejection
and with adjusting
both the LINEAR and
the
EXPONENTIAL
gain
fac-
tor
to unity.
6.131 HIGH FREQUENCY
REJECTION.
1
.
Set all
control
sliders to
their
minimum,
i.e.
down or left,
position.
2. With patch cords,
connect
the VCA output to the MIC
PREAMP
input, and
connect
the
MIC PREAMP
output
to
the PANPOT
input.
3.
Set the
MIC
PREAMP "RANGE" at
xlOOO
and GAIN
at
maximum.