RDL RU-PA40D Manual

RACK-UP ® SERIES
Model RU-PA40D
40 W Stereo Audio Power Amplifier
with VCA Control and Power Supply

VCA Controlled Stereo Audio Power Amplifier
 20 W RMS / Channel into 8  – 40 Watts Total
 15 W RMS / Channel into 4  – 30 Watts Total

Unbalanced Inputs on RCA Phono Jacks

Balanced Inputs on Detachable Terminal Block

Switch-Selectable Stereo or Mono Operation

VCA Control on Detachable Terminal Block

Compatible with RDL Remote Level Controls

External Control Using 10 K Potentiometer or 0 to 10 Vdc

Compressor/Limiter Controls Clipping

Studio Quality, Aurally Transparent Compressor/Limiter

Compressor Produces Maximized Average Output Power

Compression Enabled Using Input Level Adjustments

LED to Indicate Audio Compression Threshold

High-Efficiency Class D Operation

Thermal and Short-Circuit Protection
The RU-PA40D is a utility power amplifier in the convenient line of RACK-UP products, featuring the superior engineering and components
common to RDL products. The RU-PA40D may be rack or surface mounted with optional RACK-UP series accessories. The RU-PA40D gives you
the advantages of a quality, high efficiency stereo audio power amplifier with the added convenience of remote control!
APPLICATION: The RU-PA40D is the ideal choice in many applications where a high quality, high-efficiency utility amplifier is needed to
drive a pair of 4  or 8  speakers. It is specifically suited to amplification applications where users need to adjust the gain. Examples
include projectors or monitors with fixed audio outputs used in classrooms, boardrooms and video conferencing. The RU-PA40D is ideal
for foreground sound amplification in small to medium rooms or in a specific zone within a retail space.
The RU-PA40D features two balanced line-level inputs on a detachable terminal block. Two unbalanced line level inputs are available on
high-reliability gold plated phono (RCA) jacks. A front-panel gain control trimmer permits setting the maximum gain for each channel. The
gain range accommodates the range of typical balanced and unbalanced audio signal levels. Each of the two RU-PA40D outputs will drive
a 4  or 8  speaker or multiple speakers connected to present a 4  or 8  load to the amplifier. The output impedance is
switch-selectable on the front panel of the module.
The RU-PA40D is equipped with an internal stereo VCA for setting the output level on both amplifier channels. A detachable terminal
block provides for the connection of an external 10 K potentiometer or a 0 to 10 Vdc control voltage. RDL remote controls are available to
provide single-turn, multi-turn (rotary encoder) or pushbutton (ramp or fixed level selection) user level control. VCA control insures long
term noise-free level adjustment. Remote control is possible using audio, control or common computer network wire.
A front-panel switch is provided to sum the audio inputs to mono. In the STEREO mode, the RU-PA40D independently amplifies each
audio channel, left (L) and right (R). If speaker placement in the specified installation is incompatible with stereophonic amplification, the
INPUT MODE switch may be set to SUMMED MONO.
The RU-PA40D includes a stereo analog compressor/limiter for audio fidelity noticeably superior to conventional class D amplifiers with
digital limiting. The input GAIN settings determine whether the limiter alone is used for clipping suppression, or if the full compressor/limiter
will be used to substantially increase the average output power beyond that of a standard 40 W amplifier. A red front-panel LED flashes
when the limiter is preventing output clipping. Normal audio level signals remain unaffected by the compressor thereby preserving audio
dynamics. If the input level is increased so that the compressor is active, the LED remains dimly lit between peak flashes. The audio is
compressed according to three dynamic time constants providing aural transparency while maintaining clean, unclipped amplified audio for
input overloads of up to 20 dB. The RU-PA40D, with compression, is capable of producing average audio output levels and clarity normally
expected from stereo amplifiers with a much higher output power rating.
A blue POWER LED illuminates when the RU-PA40D is powered from its external 24 Vdc power supply (included). The module is
equipped with both thermal and output short-circuit protection. The high-efficiency Class D output stages produce minimal heat for all
levels of expected voice or music modulation. Continuous full-power operation with audio tones will not damage the amplifier, but is not
recommended.
Wherever an ultra-compact, high quality, high efficiency audio power amplifier is needed to provide reliability and unsurpassed versatility,
the RU-PA40D is the ideal choice. Use the RU-PA40D individually, or combine it with other RDL products as part of a complete
audio/video system.

RDL 659 N. 6
th

St. Prescott, AZ., USA 86301

TYPICAL APPLICATIONS:

► Projector-Mounted Amplification
► Boardrooms
► Classrooms
► Restaurant or Residential Patios
► Audio / Visual Carts
► Video Conferencing
► Localized Stereo Sound
► Foreground Sound in Retail Store Zone
 
(928) 443-9391 FAX (928) 443-9392

www.rdlnet.com