Overview
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 Ω or 8 Ω 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 or 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 Ω or 8 Ω speaker or multiple speakers connected to present a 4 Ω or 8 Ω 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 KΩ 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 stereo 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. 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.
Features:
- VCA Controlled Stereo Audio Power Amplifier
- 20 Watts RMS per Channel into 8 Ω - 40 Watts Total
- 15 Watts RMS per Channel into 4 Ω - 30 Watts Total
- Unbalanced RCA Jack Inputs; Balanced Detachable Terminal Block Inputs
- VCA Control on Detachable Terminal Block
- External Control Using 10 KΩ Potentiometer or 0 to 10 Vdc
- Compatible with RDL Remote Level Controls
- Switch-Selectable Stereo or Mono Operation
- Studio Quality, Aurally Transparent Compressor/Limiter
- Compressor/Limiter Controls Clipping
- 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
- RU-PA40D includes North American Cord; RU-PA40DE excludes Power Cord
Specifications
Inputs (4):
Line level: Balanced (+4 dBu) Left and Right, Unbalanced (-10 dBV) Left and Right
Input Impedance:
50 kΩ balanced, 20 kΩ unbalanced
Gain Adjustments (2):
Single turn, one per channel
Minimum Input Levels:
-11 dBu balanced, -18 dBV unbalanced (to cross compressor threshold)
Maximum Input Levels:
+22 dBu balanced, +12 dBV unbalanced
VCA Control:
External 0 to 10 Vdc (linear), 10 kΩ linear taper potentiometer, RDL remote controls10 Vdc VCA reference voltage output provided
Frequency Response:
20 Hz to 20 kHz (± 1 dB, 4 or 8 Ohms)*
THD+N:
< 0.1% (1 kHz, 1 W, 4 or 8 Ohms); < 1% (50 Hz to 20 kHz,)*
*measured at compressor threshold level equaling 12 W RMS (8 Ohms) output power
Compressor:
Threshold nominally 2 dB below rated output, automatically adjusting attack and release times
Crosstalk:
Better than 60 dB (1 kHz, no compression)
Noise (below 20 W RMS):
< -80 dB (VCA control 6.25V; output level 6 dB below max.) < -70 dB (VCA control max.)
Selectors (2):
Slide switches: Output Impedance 4 Ohms or 8 Ohms; Input Mode SUMMED MONO or STEREO
Output Power:
20 W RMS into 8 Ω per channel, 40 W RMS total; 15 W RMS into 4 Ω per channel, 30 W RMS total
Ambient Operating Environment:
0° C to 40° C Maximum; 20° C Recommended
Indicators (2):
Red LED: THRESHOLD LED indicates compressor activity; Blue LED: POWER on
Power Supply (included):
100 to 240 Vac, 50-60 Hz, 1.5A; 24 Vdc output to module
Package Type:
Cardboard Box
Package Dimensions:
5.125 x 2.5 x 5.875 in.
Shipping Weight:
2.15 lbs.
Tariff code:
8518.50.0000
RDL Three-Year Limited Warranty
Installation of these products by the Purchaser shall constitute Purchaser’s acknowledgement and acceptance of the terms and
conditions for sale and of this warranty, and shall constitute the Purchaser’s determination of the suitability of this product for the
Purchaser’s intended application. Radio Design Labs, Inc., also referred to as RDL®, warrants to the Purchaser that products
manufactured by RDL are free from defects in material and workmanship. This warranty applies to the period of three years from the date
of shipment, except for component parts or products purchased from other sources and supplied by RDL. Such component parts or
products bear only the warranty of the manufacturer thereof in effect at the time of shipment to the Purchaser. RDL will, without charge,
and after written notice has been received and acknowledged by RDL, repair an RDL product if proved to be defective according to the
usage of the trade, when such equipment is received by RDL at the location it designates with shipment costs prepaid by the Purchaser.
RDL shall not be liable for any expense whether for repairs, replacements, material, service, or otherwise, incurred by the Purchaser or
modifications made by the Purchaser to the product. No equipment shall be deemed defective if it shall fail to operate in a normal or
proper manner due to exposure to excessive moisture in the atmosphere, excessive temperature extremes, improper environmental
cleanliness, or any other environment not consistent with the principles of good engineering practice. In no event shall RDL have any
liability for consequential damage or expense directly or indirectly arising from the use of the products, or any inability to use it either
separately or in combination with other equipment or materials, or from any other cause, whether used in accordance with instructions or
not. This warranty is void if equipment is altered in any way by other than RDL. RDL products are NOT intended for use in life support
appliances, devices, or systems. Use of RDL products in such applications is done solely at the liability of the reseller/installer and/or end
user. RDL reserves the right to change design parameters and specifications at any time without notice. The performance measurements
reflect the products at the time of printing. This warranty is in lieu of all others, either expressed or implied. No representative is authorized
to assume for RDL any other liability in connection with RDL products.
