Stereo Audio Selector 4x1

  • Local or Remote Controlled Switching
  • Multiple Switching Control Points
  • 4 Stereo Inputs to 1 Stereo Output
  • Line-Level Audio Switching
  • Balanced or Unbalanced Inputs and Output
  • Gain Trim on Each Source
  • Controllable Using Various RDL Remote Controls
  • Open-Collector Output for Selected Input
  • Recommended Power Supply
    PS-24AS (USA)PS-24AX (International)


    The RU-ASX4D is a four channel stereo audio selector with input gain adjustments and output level metering. The inputs and outputs are connected on rear-panel detachable terminal blocks.

    Each of the four stereo line level inputs accepts either a balanced or an unbalanced signal. Each input is equipped with a rear panel screwdriver-adjustable input gain trimmer. Input signal levels between -15 dBV and +8 dBu may be set to the proper operating level as indicated by a stereo dual-LED VU meter. This assures ample headroom at all normal operating levels. The module is equipped with two identical dual-led VU meters, one on the front panel, the other on the rear panel. The maximum input level is +25 dBu.

    The RU-ASX4D was designed for absolute silent switching of audio signals using only solid-state switching circuitry.

    The output is stereo line level. Each output channel may be connected balanced or unbalanced. Each of the VU-meters, left and right, is calibrated to read +4 dBu for the corresponding balanced output.

    A front-panel LOCAL/REMOTE switch enables either the front-panel buttons or the rear-panel remote control terminals provided on detachable terminal blocks. In the LOCAL mode, four keyboard style long-life pushbuttons on the front panel are used to select one input. When a button is pushed, the corresponding audio input is fed to the output and any previously selected source is shut off. Only one source may be selected at a time. If the button for a selected source is pushed again, all inputs are turned off. An LED above each pushbutton indicates the selected source. In the REMOTE mode, inputs are selected by a sequential remote control such as an RDL D-RCS4, by a momentary remote control such as an RDL D-RC4M or by an external open-collector momentary closure to ground. The RU-ASX4D may be remote controlled from a single or from multiple locations. When a source is selected, the RU-ASX4D provides a 25 mA open-collector output to control other equipment or modules.

    Rear-panel DIP switches are provided to permanently activate the remote control terminals, to select the remote control mode (sequential or individual source selection), and upon power-up a return to either a pre-programmed source or to the last source used. The pre-programmed source is stored when the module is installed.

    The RU-ASX4D offers exceptional headroom, very low distortion, excellent crosstalk isolation, wide flat frequency response and extremely low noise with very high common-mode signal rejection. It provides exceptional audio performance for the most critical applications in a professional audio environment.

    The RU-ASX4D operates from 24 Vdc connected through a rear-panel detachable terminal block.


    Audio Inputs (4):Stereo, Line level on Detachable Terminal Block
    Input Impedance:> 20 kΩ balanced, >10 kΩ unbalanced
    Input Level (for +4 dBu output):-15 dBV to +8 dBu, adjustable on rear-panel trimmers
    Maximum Input Level:+25 dBu
    Common Mode Rejection:> 60 dB (50 Hz to 120 Hz)
    Headroom (above +4 dBu):> 20 dB (unity gain)
    Frequency Response:10 Hz to 20 kHz (±0.2 dB)
    Distortion (THD + N):< 0.01% (20 Hz to 20 kHz)
    Noise (below +4 dBu):< -85 dB (with any input selected); < -95 dB (with no input selected)
    Off Attenuation:> 85 dB (1 kHz), > 70 dB (20 kHz)
    Crosstalk:< -85 dB (1 kHz); < -65 dB (20 kHz)
    Front-Panel Switches:Momentary pushbuttons (4, 1 per input), LOCAL/REMOTE latching pushbutton
    Front-Panel Indicators (11):Power, Selected channel (4), LOCAL/REMOTE selector (2), L and R Dual-LED VU meters (4)
    Audio Output:Stereo, Line level on Detachable Terminal Block
    Output Impedance:150 Ω balanced, 75 Ω unbalanced
    Output Level:+4 dBu balanced, unbalanced output 6 dB below balanced output level
    Control inputs (5):1 mA, pulled to ground (4, source selection); 1 mA, pulled to +15 Vdc (SEL)
    Control outputs (5):25 mA, open-collector to ground
    Rear-Panel Indicators (4):L and R Dual-LED VU meters
    RDL Remote Control Compatibility:D-RC4M, D-RCS4
    Power Connection:Detachable Terminal Block
    Power Requirement:24 Vdc @ 150 mA, Ground-referenced
    Ambient Operating Environment:0° C to 55° C
    WEEE Weight:1.26 lbs
    Shipping Weight:1.515 lbs
    Tariff Code:8543.70.9860

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    CAD FilesUnitsFormat
    Engineering Functional BlockAmericanDXF
    Panel Diagram - FrontAmericanDXF
    Panel Diagram - RearAmericanDXF
    Panel Diagram - FrontMetricDXF
    Panel Diagram - RearMetricDXF
    High Res ImagesFormat
    Declaration of Conformity


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