HIGH QUALITY HEADPHONE LISTENING STATION
Professional Stereo Headphone Amplifier with Level Control
Two RDL ST‑VCA3 Voltage Controlled Amplifiers are used to adjust the audio level using an RDL AMS‑10K Linear Potentiometer at the listening location. Audio does not pass through the potentiometer, assuring years of scratch‑free adjustment. The RDL ST‑SH2 Stereo Headphone Amplifier drives headphones of any impedance (8 ohms or high impedance) from consumer or professional audio sources. The exceptional low noise (better than 100 dB below operating level), low distortion, audio clarity and excellent crosstalk performance makes this module ideally suited to a wide variety of demanding audio applications. The AMS‑1/4F is a female Â¼â€ stereo phone jack which is mounted together with the AMS‑10K to an RDL D‑D2 Double Plate installed in an RDL DC‑1G Surface Mount Box. The installation is completed with an RDL CP‑1 Cover Plate.
SWITCHER SELECTS STEREO AUDIO SOURCE
Local Momentary Pushbuttons Provide Silent Soft-Switching of Four Consumer Audio Sources
The RU‑ASX4D Audio Selector allows the user to select one (or none) of four stereo consumer audio sources to feed the power amplifier. Long‑life keyboard‑style momentary pushbuttons activate silent solid‑state audio switching circuits. The active source is quickly ramped up when it is selected, providing an aurally pleasant switching transition. Solid‑state switching results in years of reliable operation free from switch noise and intermittent connections common to many inexpensive unbalanced audio switchers. Each RU‑ASX4D input may be balanced or unbalanced; the RU‑ASX4D may be remote controlled.
AUTOMATIC LOUDNESS EQUALIZER
Improves Sonic Fullness at Low Listening Levels
An unbalanced stereo audio signal (RCA jacks or Mini‑jack) from an external source (MP3 shown) is summed and converted to balanced mono using the DS‑CIJ3 Consumer Input Jack plate. An RDL FP‑PA18 18 Watt Audio Power Amplifier feeds outdoor loudspeakers in the patio seating area. In the absence of an audio input, a digital timer within the FP‑PA18 is enabled to switch the class D output stage off. When this sleep mode is active, the amplifier module and its included RDL power supply consume less than 1 W of mains power. The wall‑mounted DS‑RLC10K Remote Control allows users to adjust the audio level on the patio. The DS‑RLC10K controls the ST‑VCA3 Voltage Controlled Amplifier which sets the audio input level to the power amplifier and also controls the loudness equalization through the ST‑LEQ1. As the volume is turned down on the DS‑RLC10K, the ST‑LEQ1 increases the bass frequencies. As the listening level is increased by the remote control, the loudness equalization is progressively decreased until the audio is flat at higher listening levels. The DIRECT INPUT on the ST‑LEQ1 is intended for a paging signal input which will always be the same level regardless of the setting on the remote volume control.
5.1 SURROUND SOUND REMOTE LEVEL CONTROL
Multi-Channel Level Control for Theater or Control Room
The RU‑VCA6A Six Channel Digitally Controlled Attenuator and RLC10K Remote Level Control are used to increase and decrease the level of the 5.1 Surround Sound source feeding the amplifiers.
The RU‑VCA6A offers clickless level adjustment, accurate tracking and outstanding wide‑band, low‑noise studio quality performance. It can be controlled remotely by a variety of RDL or third‑party controls and/or locally via front‑panel pushbuttons. Each audio input and output may be configured balanced or unbalanced. Multiple RU‑VCA6As and/or RU‑VCA2As may be linked together for single‑point level control of 7.1, 10.2 or 22.2 surround sound systems.
STEREO REMOTE AUDIO LEVEL CONTROL
Studio Quality Volume Adjustment for Professional and Consumer Applications
The RU‑VCA2A Two Channel Digitally Controlled Attenuator and RLC10K Remote Level Control are used to increase and decrease the level of the Stereo Sound source feeding the amplifiers.
The RU‑VCA2A offers clickless level adjustment, accurate tracking and outstanding wide‑band, low‑noise studio quality performance. It can be controlled remotely by a variety of RDL or third‑party controls and/or locally via front‑panel pushbuttons. Each audio input and output may be configured balanced or unbalanced. Multiple RU‑VCA2As and/or RU‑VCA6As may be linked together for single‑point level control of 7.1, 10.2 or 22.2 surround sound systems.
FOUR INPUT UNBALANCED STEREO SWITCH
High Performance Switching of Consumer Audio Sources
Many inexpensive unbalanced audio switches use mechanical contacts to switch the audio. This leads to switch noise and unreliable operation, particularly after the switches have been in service for several months. The RDL EZ‑SX4 provides long‑life, silent switching by using solid‑state technology for all audio switching. The EZ‑SX4 allows the user to select one of four unbalanced stereo sources. The output feeds the power amplifier driving the stereo speakers. The EZ‑SX4 output level is adjustable using a front‑panel knob, allowing a user to select a source and adjust volume from one location.
The EZ‑SX4 is shipped with a high efficiency power supply that connects to a locking dc power jack.
SWITCH MULTIPLE STEREO AUDIO SOURCES
Monitor Audio Outputs with Intergrated Headphone Amplifier
The EZ‑HSX4 has an integrated headphone amplifier that adds versatility to the four input stereo switcher. The EZ‑HSX4 uses solid‑state switching to insure reliability and so that mechanical switch noise does not affect signal quality. The front‑panel headphone jack monitors the line‑level output which may be used to feed sound systems in different rooms or to feed recording equipment. If the line output is not used, the EZ‑HSX4 can serve as a headphone amlifier with four switched inputs. The line‑level stereo output can be switched to unity (fixed) gain or can follow the level set by the front‑panel volume knob that adjusts the headphone output level.
The EZ‑HSX4 is shipped with a high efficiency power supply that connects to a locking dc power jack.
COMPOSITE VIDEO DISTRIBUTION
Distribute Video to Remote Location in House
This application demonstrates how to distribute a composite video signal to a remote location in a house. The EZ‑VDA2Râ€™s bandwidth is > 400 MHz which ensures a high quality picture. Gain and equalization controls on the front panel allow adjustments for long cable runs. The EZ‑VDA2R provides professional performance in a very compact package.
The EZ‑VDA2R is shipped with a high efficiency power supply that connects to a locking dc power jack.
ADD A SUBWOOFER TO A FULL-RANGE SOUND SYSTEM
Crossover Module Allows Mono Amplifier to Drive a Passive Subwoofer
The RDL ST‑CX2S Subwoofer Crossover Filter provides active line‑level equalization for the addition of a subwoofer to a sound system equipped with full‑range speakers. The ST‑CX2S high‑impedance line‑level stereo inputs bridge existing line‑level stereo sources. Each input is isolated to prevent the introduction of any crosstalk to an existing stereo signal. The low impedance (150?) line‑level output can drive low or high impedance lines. Inputs and output may be wired balanced or unbalanced.
PATIO AUDIO SYSTEM
Home Entertainment System with 4 Outdoor Rock Loudspeakers
A stereo unbalanced audio signal from a home entertainment system is summed and converted to a balanced mono signal using the TX‑J2 Unbalanced Input Transformer. An RDL FP‑PA20A 20 Watt 70 Volt Audio Power Amplifier powers four 70 Volt outdoor rock speakers in a patio seating area. Each speaker is tapped at 5 Watts, for a total of 20 Watts. The volume is controlled by the home entertainment system. Using a 70 Volt system allows for the use of smaller cable sizes which reduce system costs and simplify the installation. An RDL FP‑PA20B 20 Watt 25 Volt Audio Power Amplifier may be used in place of the FP‑PA20A if a 25 Volt system is desired.
7.1 SURROUND SOUND REMOTE LEVEL CONTROL
Multi-Channel Level Control for Theater or Control Room
The RU‑VCA6A (6 channel) and RU‑VCA2A (2 channel) Digitally Controlled Attenuators are arranged in a MASTER/SLAVE configuration to allow single point level control of the 7.1 surround sound source feeding the amplifiers. Either VCA module may serve as master. This application uses an RLC10K Remote Level Control to control the RU‑VCA6A. The RU‑VCA6A control output port is connected to the control input of the RU‑VCA2A, which is set to slave mode. The RU‑VCA2A follows the level setting of the RU‑VCA6A. Multiple VCA modules may be slaved from a single master module.
The RU‑VCA6A and RU‑VCA2A offer clickless level adjustment, accurate tracking and outstanding wide‑band, low‑noise studio quality performance. They can be operated remotely by a variety of RDL single or multi‑point controls, third party controllers and/or locally via front‑panel pushbuttons. Each audio input and output may be wired balanced or unbalanced. The RU‑VCA6A and the RU‑VCA2A may be used independently in 5.1 surround and stereo systems.
Interface a Turntable to Audio Equipment with Line Inputs
This application illustrates how to interface a turntable with common audio equipment not equipped with phono inputs. The EZ‑PH1 is a compact phono preamp that produces an unbalanced stereo output using the RIAA equalization curve. Input and output connections are made through gold‑plated RCA jacks for easy connection to an amplifier auxiliary input or a CD recorder line input. Gain trimmers for each channel and dual‑LED VU meters make it easy to set preamp levels. The EZ‑PH1 is the ideal solution for phonograph record playback or dubbing. A grounding screw is provided for connection to the tone arms of quality turntables.
The EZ‑PH1 is shipped with a high efficiency power supply that connects to a locking dc power jack.
SIMPLE HOME AUDIO
Wall Plate Audio Routing
This simple setup allows the audio from a computer or other audio source to be shared with the audio system in another room. In this example the audio is fed from the computer into a wall plate that is wired directly to a wall plate in the second room. The two wall plates are connected with two balanced shielded audio cables. These wall plates are avaliable in RDLâ€™s grey/white color or in stainless steel. Custom labeling is available.
RF SUPPRESSION IN AUDIO OR CONTROL CIRCUITS
RFI Suppressed on Six Signal Conductors
The ST‑FS6 Ferrite Suppressor / RF Filter is used to attenuate excessive RF interference (RFI) induced in the wiring conductors by a nearby communications tower. The passive ST‑FS6 provides six isolated channels of highly effective ferrite RF suppression without capacitance to ground or series resistance. Two ground terminals are provided to be used as tie points for connecting cable shields (not pictured). The ground lugs have no internal connection to the suppression circuitry. Each of the six I/O terminals may be used independently for the suppression of RF on Audio, dc power or logic control signal conductors. RF interference on audio and control wiring causes unwanted audio noise or instability in control circuits. The ST‑FS6 is normally installed at the rack where signals are received. It is possible that interference may interfere with audio or control sending equipment, making it beneficial to install a suppressor module at both ends of the long interconnection lines.
PATIO AUDIO SYSTEM
MP3 Music Player with Two Outdoor Rock Loudspeakers
An outdoor patio is equipped with a DS‑CIJ3 Consumer Input Jack DecoraÂ® plate that provides connectivity for an MP3 music player or other stereo audio source. The DS‑CIJ3 provides a balanced mono sum of the MP3 player source to the ST‑PA18 Audio Power Amplifier. The ST‑PA18 is a high‑efficiency, Class D power amplifier that provides 18 Watts RMS to the rock speakers. The ST‑PA18 has an integral audio compressor to control clipping. The DS‑CIJ3 (mounted in a CP‑1S Stainless Steel Single Gang Cover Plate and SMB‑1G Surface Mount Box) and the ST‑PA18 are mounted in a standard weatherproof box.
STEREO KARAOKE SYSTEM
Stereo Mixer Amplifier Adds Compression and Equalization
The EZ‑MXA20 is a feature‑rich mixer amplifier. In addition to two stereo line level inputs, the mixing section of the EZ‑MXA20 features a high quality mic preamplifier with switch‑selectable phantom power. Output power is 10 Watts RMS per channel into 8 Ohm speakers (8 Watts RMS per channel for 4 Ohm speakers). The power amplifier features a compressor, with a front‑panel LED indicator, to protect against clipping. The front panel also features a two band equalizer for tailoring frequency response. The compact size of the EZ‑MXA20 makes it the ideal choice when there is limited space for a full‑featured mixer amplifier.
The EZ‑MXA20 is shipped with a high efficiency power supply that connects to a locking dc power jack.
INTERFACE PROFESSIONAL & CONSUMER EQUIPMENT
Audio Format Conversion with Metering and Level Controls
It is frequently necessary to use professional and consumer audio equipment in the same environment. The EZ‑AFC2 provides both balanced‑to‑unbalanced and unbalanced‑to‑balanced conversion for stereo audio line‑level signals. Superior electrical performance ensures audio transparency. All channels are monitored via dual‑LED VU meters. Front panel knobs allow for easy level adjustment. The fully connectorized EZ‑AFC2 makes this common interface task as easy as possible.
The EZ‑AFC2 is shipped with a high efficiency power supply that connects to a locking dc power jack.
POWERING MULTIPLE STICK-ONS FROM SINGLE SUPPLY
Distributed dc Power From Current-Limited Switching Power Supply
The low current consumption of STICK‑ON modules allows multiple modules to be powered from a single supply. The ST‑PD5U distributes power from any RDL current‑limited switching power supply to up to five modules with a total current requirement of 2 amperes or less. RDL 24 Vdc switching power supplies (purchased separately) are available with current ratings of 500 mA, 1 A and 2 A. All meet ENERGY STAR Level V standards.
CONNECT A TURNTABLE TO EQUIPMENT WITH LINE INPUTS
Interface Your Turntable with Modern Consumer or Pro Equipment With No Phono Inputs
After the introduction of digital audio sources such as the CD and MP3, many manufacturers of both consumer and professional audio equipment omitted traditional phono inputs in favor of additional line inputs. The ST‑PH1 Stereo Phono Preamplifier provides a low‑noise RIAA preamplified interface between a turntable and any analog balanced or unbalanced line‑level inputs on a mixer, processor or amplifier. Placing the ST‑PH1 as close to the turntable as possible allows the wiring between the tone arm pickup and the preamplifier to be kept as short as possible for optimum low‑noise system performance.
ACTIVE LINE-LEVEL CROSSOVER FOR BI-AMPLIFIED SYSTEM
Adjustable Line-Level Low-Frequency and Full-Range Crossovers
Each channel in this system is equipped with a separate full‑range loudspeaker and woofer, driven by a separate amplifier channel. The ST‑CX2 Line‑Level Crossovers are installed between the line‑level source and two dual‑channel power amplifiers. The FULL‑RANGE output of each ST‑CX2 feeds the FULL‑RANGE (100 Hz â€“ 30 kHz) amplifiers while the WOOFER(40 Hz â€“ 165 Hz) outputs deliver signal to the amplifiers driving the woofers. The equalization curve of each output is individually adjustable. A single ST‑CX2 would be used in a mono system. An RDL ST‑CX2S Subwoofer Crossover may be added if it is desired to add a subwoofer to this system. Note: The FULL‑RANGE output of the ST‑CX2 could also be used in applications where a line‑level high‑pass filter is required to roll‑off frequencies below 100 Hz.
COMPOSITE VIDEO AND STEREO AUDIO SWITCHING
Select Between 4 Composite Video and Stereo Audio Sources
Switching between multiple A/V sources is a common task in home theatres. This diagram illustrates the EZ‑AVX4 being used to switch between a DVR, DVD player, a gaming console and a VCR. The RDL EZ‑AVX4 Composite Video and Stereo Audio Input Switcher features solid state switching on the audio and video signals making them immune to mechanical switch noise and ensures a long life of reliable operation.
The EZ‑AVX4 is shipped with a high efficiency power supply that connects to a locking dc power jack.
ADD PATIO AUDIO TO HOME AUDIO SYSTEM
User Audio Input Amplified to Outdoor "Rock" Speakers
An unbalanced stereo audio signal (RCA jacks or Mini‑jack) from an external source (Computer, cassette player, CD player, DVD player, radio, etc.; MP3 player shown) is summed and converted to balanced mono using the DS‑CIJ3 Consumer Input Jack plate. This signal is sent to the Home Audio System controller which is used to select the DS‑CIJ3 as the active source. Volume is controlled by the home audio system or by the MP3 player or other user‑provided audio source. The TX‑J2 balances a designated line‑level audio output from the home system and sends the signal to the RDL FP‑PA20A 20 Watt Audio Power Amplifier that feeds 70 Volt outdoor "rock" loudspeakers in the patio seating area. Each speaker is tapped at 5 Watts.
PROTECTING VOICE COILS IN COMPRESSION DRIVERS
High Pass Filter Rolls Off Damaging Low Frequencies
Voice coils in paging horn compression drivers are easily destroyed by excessive low frequencies. The ST‑HP3, installed prior to the input of the power amplifier, protects the voice coil by attenuating low frequencies. The installer can choose from two separate outputs, 300 Hz or 500 Hz, depending on the frequency response of the installed horns. Low frequencies are attenuated by 18 dB per octave below the selected cutoff frequency. Use of the ST‑HP3 eliminates the need for calculating and installing a capacitor on each driver, and provides a steeper attenuation slope for better protection and intelligibility.