Rane FVL 22 User Manual

Professional Audio Products Data Sheet

REMOTE VCA/LIMITER

FVL 22 Remote VCA/Limiter

General Description

FVL 22

The Rane FVL 22 Remote VCA/Limiter is a
stereo (2-channel) general purpose Flex building
block consisting of two remotely controlled,
professional recording quality VCA’s (voltage­controlled amplifiers) along with two Limiters.
Each channel operates independently or they
slave together to form a locked stereo pair. The
FVL 22 uses Analog Devices VCA’s for their
superb noise and distortion performance.

A unique voltage calibration feature allows
using a wide range of VCA control voltages.
Ramp voltages may vary from standard +5VDC
digital levels to +24VDC doorbell levels. Three
LED indicators make calibration easy and
positive.

Alternatively, the FVL 22 provides a tightly
regulated +10VDC reference voltage for use with
external potentiometer control. Potentiometer
values may vary over a wide range of 5k to 100k
ohms, using linear taper. Either type of control

Features

• TWO INDEPENDENT OR SLAVED
CHANNELS

• RECORDING QUALITY VCA’s

• VOLTAGE RAMP OR
POTENTIOMETER CONTROL

• UNIQUE CALIBRATION ALLOWS
5-24VDC CONTROL

• NOISE REJECTION FILTERS ON
CONTROL PORTS

Parameter Specification Limit Units Conditions/Comments

Max In/Out +20 1 dB Balanced
VCA Control Voltage 5-24 10% VDC
Control Potentiometer Range 5k to 100k Audio or Linear Taper 20% Ohms (Linear Taper: See Rear)
VCA Tracking 0 to -50: less than 0.75 dB Driving V1 & V2 Together

-50 to -80: less that 1.0 dB Driving V1 & V2 Together
VCA Range 0 to -80 1 dB Maximum Attenuation
VCA Control Law 0 = On; 5-24 = Off VDC Voltage Applied to V1 or V2
Control Noise Filter 3Hz, 18dB/Octave 5% Butterworth
Control Hum Rejection -74 @ 50Hz; -78 @ 60Hz 2 dB
Limiter Threshold Range -20 to +20 2 dBu Balanced Output Level
Overall Gain 0 0.5 dB
THD + Noise 0.022 0.008 % +4dBu, 20-20kHz, +20dB Threshold
IM Distortion (SMPTE) 0.015 0.005 % 60Hz/7kHz, 4:1, +4dBu
Signal-to-Noise Ratio 107 2 dB Balanced Out re +20dBu, 20kHz BW

91 2 dB Balanced Out re +4dBu, 20kHz BW
Channel Crosstalk 90 2 dB 20-20kHz
Maximum Current 500 mA RMS Current From Remote Supply

benefits from built-in AC noise filters provided
on the VCA control lines. The noise filters
prevent all false level changes caused by hum and
noise induced on the DC control lines.

The Limiters operate over a wide balanced
output range of -20dBu to +20dBu, and feature
the same proven technology first made famous by
Rane’s popular DC 24 Dynamic Controller. The
important Auto-Slave feature first introduced in
the FPL 44 is incorporated as well.

The VOLTAGE CALIBRATION and
LIMITER controls are screwdriver-adjust type,
with hole-plugs for additional security. Inputs
and outputs are fully balanced, but operate
unbalanced when required. All interconnection is
done using convenient, secure and economical
terminal strips. Additionally, ¼" TRS jacks
provide quick single-cable interconnect to
console patch points wired per the tip=send,
ring=return convention. VCA control always uses
the terminal strip.

• PRECISE +10VDC REFERENCE
VOLTAGE

• ACCEPTS WIDE RANGE OF
POTENTIOMETERS

• 40dB LIMITER RANGE

• BALANCED IN/OUT VIA TERMINAL
STRIPS

• ¼" PATCH JACK FOR INSERT
LOOPS

FVL 22

Professional Audio Products Data Sheet

REMOTE VCA/LIMITER

Rear Panel Block Diagram

Applicaton Information

Use the FVL 22 anytime you
need one or two channels of high
quality VCA remote control of
signal level. Additionally, the FVL
22 provides two channels of
Limiting, practically for free.

VCA Control. The FVL 22
follows the usual convention of

zero volts turns the VCA fully on,
and some maximum positive voltage
turns the VCA fully off. Choose

between potentiometer, voltage
ramp or switch control. The FVL 22
accepts a wide range (5k-100k) of
linear taper potentiometers. A
reference voltage of 10VDC is
provided by the FVL 22, or you may
use your own anywhere in the range
of +5VDC to +24VDC. A unique,

simple calibration adjustment makes using external voltage
references extremely easy. Similarly, voltage ramps with a
maximum of +5VDC to +24VDC control the FVL 22 as well.
Or, for simply two-state systems (e.g., On/Off, or On/-20dB,
or -20/-60, or whatever), a switch closing between ground and
any voltage up to +5VDC to +24VDC controls the VCAs.
Note: When properly calibrated, the CAL indicator lights only
for VCA fully off; all other conditions light the LOW indica­tor.

Limiter Section. The limiters in the FVL 22 use the same

topology as the Rane FPL 44 Quad Limiter. This is a feed­back, as opposed to a feedforward, design. The control circuit

for the limiter monitors the output of the VCA, not the input
of the unit. Any time the output of the VCA exceeds the
threshold set on the front panel (calibrated for both balanced
and unbalanced use), limiting begins. The ratio of the limiter
is set automatically and is a function of the excess level the
system is attempting to deliver above the preset threshold.
The attack and release times of the limiter are an automatic
function of the speed at which the input signal is attempting
to drive the output of the unit above the threshold level.

The AUTO-SLAVE limiter function allows both channels
to track, or be slaved, together. When the LIMITER switch is
in the AUTO-SLAVE position, limiting occurring on either
channel causes equivalent limiting in the other channel. This
retains the imaging and spectral balance in stereo applica­tions.

Using Linear Taper Controls. Audio (or log) taper pots
give the best attenuation distribution around the control, but
linear pots are easier to get. You can approximate an audio
taper by adding a resistor to the slider per the diagram shown.

Copyright 1993, Rane Corporation 10802 47th Ave. W., Mukilteo, WA 98275-5098 [phone]

Printed in the U.S.A. on Recycled Paper

All features & specifications subject to change without notice 520-255 793