Rane FVL 22 - Manual (Page 4)

All features & specifications subject to change without notice. 520-254 JUL95 Printed in the U.S.A. on Recycled Paper
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OPERATING INSTRUCTIONS
The FVL 22 is a two Channel Voltage Controlled Ampli-
fier (VCA) providing the following functions—an audio level
control, and a limiter.
REMOTE AUDIO LEVEL CONTROL
Applying a control voltage to the V1 or V2 terminals sets
the gain through the unit. This voltage is controlled from a
remote potentiometer, switch or ramp. A 10 volt reference is
provided at the VREF terminal or you may provide your own
5 to 25 volt source remotely.
With zero volts applied to V1 or V2, there is no attenua-
tion of the signal (unity gain). As the control voltage in-
creases, the signal attenuates. When the maximum calibrated
control voltage is applied, there is maximum attenuation of
the signal.
To calibrate the unit, apply the maximum voltage (an
unattenuated pot, a closed switch, or maximum voltage ramp)
to V1. Adjust the screwdriver VOLTAGE CALIBRATION
control until the CAL indicator is illuminated. This allows the
maximum attenuation over the control voltage range.
Figures 1-4 show wiring diagrams to suit most applica-
tions.
LIMITER
The limiter function limits the maximum output level of
the FVL 22. To set the limiter, rotate the screwdriver-adjust
LIMITER control fully counterclockwise. Then advance it
clockwise to the maximum dBu output desired. Note that this
control has two scales, one for balanced operation and one for
balanced operation. Be sure to use the proper scale for your
application.
When used in conjunction with the audio level control
feature above, note that the limiter takes precedence. The
audio level can only be controlled when it is under the
threshold of the limiter (i.e. when the LIMIT indicator is off).
The limiter has an additional feature—AUTO-SLAVE.
This switch ties the control circuitry of the two limiters
together. If either Channel’s level exceeds its set threshold,
both Channels limit the same amount. This retains spectral
balance for bi-amped loudspeakers or preserved stereo image
in stereo applications.
Remember, Auto-Slave only affects the limiters, not the
VCAs.
Figure 1. Remote Pot Using FVL 22 Reference
Figure 2. Remote Switch With Remote Reference
Figure 3. Voltage Ramp (from +5 to +24VDC)
Figure 4. Remote Pot With Remote Reference
CHASSIS GROUNDING
Rane Flex modules are supplied with a rear or side
mounted ground-lift switch. The unit is shipped with this
switch in the “grounded” position, tying circuit ground to
chassis ground. If after hooking up your system it exhibits
excessive hum or buzzing, there is an incompatibility in
the grounding configuration between units somewhere.
Your mission, should you accept it, is to discover how
your particular system wants to be grounded. Here are
some things to try:
1. Try combinations of lifting grounds on units that are
supplied with ground lift switches or links.
2. If your equipment is in a rack, verify that all chassis are
tied to a good earth ground, either through the line cord
grounding pin or the rack screws to another grounded
chassis.
3. Units with outboard power supplies do NOT ground
the chassis through the line cord. Make sure that these
units are grounded either to another chassis which is
earth grounded, or directly to the grounding screw on
an AC outlet cover by means of a wire connected to a
screw on the chassis with a star washer to guarantee
proper contact.
Please refer to Rane Note 110 (supplied with your unit
and available on request at no charge if you lose it) for
further information on system grounding.
IMPORTANT NOTE