RDL RACK-UP Series User manual

RACK-UP®SERIES
Models RU-VCA2A & RU-VCA6A
Digitally Controlled Attenuators
Local or Remote Audio Level Control
Mono or Stereo Attenuation (RU-VCA2A)
Six Channel / Surround Attenuation (RU-VCA6A)
Noiseless Zero-Crossing Adjustment Steps
96 dB Attenuation Range in 0.5 dB Steps
Data Bus Provides Adjustment of Multiple Modules
Multiple Remote Control Locations Possible
Precise Level Tracking on Each Channel
Balanced or Unbalanced Line Inputs/Outputs
Adjustable Ramp Up/Down Rates
Controllable Using Various RDL Remote Controls
Selectable Level Control Options:
Pushbuttons (Internal or External)
Momentary Pulses (External/Rotary Encoder)
0 to10 Vdc or 10 kPotentiometer
Selectable Power-Up Return to PRESET or LAST Level
Selectable MASTER/SLAVE Mode for Control
Expansion
APPLICATION: The RU-VCA2A is a full-featured studio-quality dual-channel audio attenuator module for local and/or remote
control of balanced or unbalanced line-level sources. The RU-VCA6A has all the features of an RU-VCA2A with four additional
audio channels for level control of surround sound (5.1) or six individual analog audio channels. Each module can be remote
controlled from a single or multiple locations. Rear-panel terminals provide flexible control options using a variety of RDL remote
controls or OEM equipment.
Audio levels are controlled in 0.5 dB steps using noiseless zero-crossing digital attenuators for optimum reliability, precise tracking
and long-term click-free service. Exceptional wide-band low-noise performance makes the RU-VCA2A and RU-VCA6A suited to
level adjustment in the most demanding applications. Rear-panel inputs and outputs may each be wired balanced or unbalanced.
The RU-VCA2A and RU-VCA6A power up in one of two operating modes set by a rear-panel switch.
MOM (momentary) Mode
In the MOM (momentary) mode, audio level is controlled by momentary pushbuttons or pulses. Remote terminals and front-panel
pushbuttons are provided for up and down ramping control. If either button is held in, the audio will ramp automatically. If a button
is pulsed (< 0.5 second), the audio will increment one step. The time of both the UP and DOWN ramps is individually adjustable
on the front panel. Pushing remote UP and DOWN buttons simultaneously, or pressing the front-panel GO TO PRESET button,
returns the audio to a preset level. The preset level is stored by adjusting the desired level using the UP and DOWN buttons, then
pressing and holding the front-panel PRESET button for 3 seconds. A rear-panel switch sets the audio power-up level to either the
preset level or the last level setting used. Multiple remote control locations are possible in the MOM mode. External control pulses
may be either of positive polarity or pulled-to-ground (open-collector).
0 to 10 VDC Mode
In the 0 to 10 VDC mode the preset function is disabled and the audio level is controlled by a remote 10 klinear taper pot or by
0 to 10 Vdc. A single remote control location is possible using a remote 10 kpot.
In both operating modes, two separate 0 to 10 Vdc outputs are provided. The linear RAMP output drives the level display on RDL
remote controls; the EQ RAMP output is used to control an automatic RDL Loudness Equalizer (see ST-LEQ1). A front-panel
10-LED string display indicates the relative audio level. Control expansion is possible using the EXTERNAL CONTROL DATA
jacks. One module can be set as a MASTER module to control the level of one or more additional RU-VCA2A or RU-VCA6A
modules set to the SLAVE mode.
Use the RU-VCA2A and RU-VCA6A individually, or combine them with other RDL products as part of a complete system.
RDL 659 6th St. Prescott, AZ., USA 86301 [phone] FAX [phone] www.rdlnet.com

RACK-UP®SERIES
Models RU-VCA2A & RU-VCA6A
Digitally Controlled Attenuators
EXTERNAL CONTROL OPTIONS (SEE ALL RDL REMOTE CONTROL OPTIONS ON THE
RU-VCA2A AND RU-VCA6A PRODUCT PAGES OF THE RDL WEBSITE: www.rdlnet.com)
TYPICAL PERFORMANCE
Inputs (2, RU-VCA2A; 6, RU-VCA6A): >10 kBalanced bridging, or Unbalanced, line level
Frequency Response: 10 Hz to 50 kHz (+/- 0.5 dB)
THD+N: < 0.005% (20 Hz to 20 kHz)
Gain: Adjustable from unity to <–96 dB
Step Size: 0.5 dB
Headroom: > 18 dB (above +4 dBu)
Residual Noise: < -90 dB (referred to +4 dBu at unity gain)
CMRR: <-65 dB (50 to 150 Hz)
Crosstalk: <-95 dB (1 kHz, typ.); < -85 dB (20 Hz to 5 kHz); < -75 dB (5 kHz to 20 kHz)
Ramp Times: 0.5 second delay; then: 3 seconds to 10 seconds
(UP and DOWN times individually adjustable on front panel)
Indicators (10): Front-panel LEDs indicating relative audio level (8), MAX condition (green), MIN condition (red)
Audio Output (2, RU-VCA2A; 6, RU-VCA6A): 150 balanced (may be connected unbalanced)
Ramp Output: 0 to 10 Vdc, (Ground-referenced) Note: Not intended to drive additional VCA 0-10V inputs
EQ Ramp Output: 0 to 10 Vdc, (Ground-referenced) Note: dc taper intended only to drive RDL Loudness EQ (ST-LEQ1)
Power Requirement: 24 Vdc @ 120 mA, Ground-referenced (RU-VCA2A); 24 Vdc @ 200 mA, Ground-referenced (RU-VCA6A)
Ambient Operating Environment: 0° C to 50° C
Case Dimensions: 5.75” (14.6 cm) W x 1.65" (4.18 cm) H x 3.54” (9.0 cm) D;3.9" (9.9 cm) D with connectors
Installation/Operation
EN55103-1 E1-E5; EN55103-2 E1-E4
Typical Performance reflects product at publication time
exclusive of EMC data, if any, supplied with product.
Specifications are subject to change without notice.
Radio Design Labs Technical Support Centers
U.S.A. [phone], [phone]; Fax: [phone]
Europe [NH Amsterdam] (++31) 20-6238 983; Fax: (++31) 20-6225-287
891-3455
POWER UP SETTINGS
Before applying power, set the POWER UP switches:
1Set to LAST if the module should power-up to the last level setting;
Set to PRESET if the module should power-up to the stored preset
level.
2Set to MOM (momentary) if module levels are to be adjusted using
front-panel buttons or using buttons, remote controls or open-
collector pulses connected to the rear-panel UP and DN terminals.
3Set to MASTER if this module is either operating on its own or is
intended to control the level of additional modules; Set to SLAVE if
this module is to be controlled by another module. (Note: The SLAVE
mode inactivates all front and rear panel control of the module.)
REAR PANEL layouts showing balanced and
unbalanced wiring examples.
Note: The EQ RAMP controls an
RDL ST-LEQ1 for automatic
"loudness" adjustment. See
ST-LEQ1 data sheet for details.
NOTE: This equipment has been tested and found to
comply with the limits for a Class B digital device, pursuant
to part 15 of the FCC Rule. These limits are designed to
provide reasonable protection against harmful interference
in a residential installation. The equipment generates,
uses and can radiate radio frequency energy and, if not
installed and used in accordance with the instructions,
may cause harmful interference to radio communications.
However, there is no guarantee that interference will not
occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception,
which can be determined by turning the equipment off an
on, the user is encouraged to try to correct the
interference by one or more of the following measures:
Reorient or relocate the receiving antenna
Increase the separation between the equipment
and receiver
Connect the equipment into an outlet on a circuit
different from that which the receiver is
connected.
Consult the dealer or an experienced radio/TV
technician for help.
POTENTIOMETER CONTROL
Enable potentiometer control by setting
POWER UP switch 2 to 0 TO 10 VDC.
1-TURN REMOTE CONTROL
Enable remote control by setting
POWER UP switch 2 to 0 TO 10 VDC.
EXTERNAL RAMP CONTROL
Enable external ramp control by setting
POWER UP switch 2 to 0 TO 10 VDC.
MULTIPLE REMOTE LOCATIONS
Enable pushbutton control by setting
POWER UP switch 2 to MOM (momentary).
OPEN-COLLECTORS/SWITCHES
Enable momentary "pull to ground" control
by setting POWER UP switch 2 to MOM.
MASTER/SLAVE CONNECTIONS
A VCA module set as MASTER (switch 3) is able to control the level on multiple modules. The EXTERNAL CONTROL
DATA OUT jack provides data to control additional modules. Connect the OUT jack to the IN jack of the first adjacent
module. Connect the OUT jack of the first adjacent module to the IN jack of the second adjacent module. Connect
additional modules in the same manner. Each connected module must be set to SLAVE mode (switch 3) as shown.
OPERATION
(Note: The Power Up CTRL switch must be set to MOM to activate the front-panel buttons.)
LEVEL ADJUSTMENT: Momentarily press the UP or DOWN button to step the level 0.5 dB. Press and hold to
ramp the level up or down.
RAMP TIME: Adjust the TIME controls for the desired ramp rate. (Note: TIME "-" is fastest; TIME"+" is slowest)
GO TO PRESET: Press this button to return the audio level to the stored preset value.
STORE PRESET LEVEL:
1] Set the audio level to the desired volume using the front-panel (or external) UP and DOWN buttons.
2] Press and hold the GO TO PRESET button (3 seconds) until the front-panel level LED flashes.
OBSERVE AUDIO LEVEL: The relative audio level is displayed on the LED string display. The level is displayed
in both the MOMentary and 0 to 10 VDC operating modes. (Note: The LED string display increments do not
directly correspond to the LED level increments on RDL remote controls.)