Voltage Controlled Amplifier

  • Audio Level Control from a DC Voltage
  • Audio Level Remote Control
  • Two Wire with Shield or Three Wire Control
  • VCA with Microphone or Line Level Input
  • VCA with Line-Level Output
  • VCA with LED Metering of Operating Level
Recommended Power Supply ( Not Included )
PS-24AS (USA)PS-24AX (International)


The ST-VCA3 is a high performance voltage controlled amplifier with two inputs and one output. The line input is designed to accept an input signal with operating levels between -20 dBV and +4 dBu. The microphone input accepts low or high impedance microphones with output levels from –60 to –44 dBu. Only one of the inputs may be used at a time.

A multi-turn trimmer is provided for setting the correct input gain according to the dual-LED VU meter located directly in front of the gain control. The intended output level is +4 dBu for 10 Vdc at the CTRL input terminal. The green metering LED begins illuminating at 15 dB below +4 dBu. The green LED progresses to full intensity at +4 dBu. The adjacent red LED illuminates at +4 dBu. Terminals are provided for connection of an external ramp generator (0 to 10 Vdc) or a linear taper 10 kΩ potentiometer remote control. The RDL RLC10K is most commonly used.

The ST-VCA3 is used in applications requiring smooth audio level control from a remote control panel, potentiometer or dc voltage (0 to 10 V). Installation in series with the audio input of a power amplifier allows remote control of that amplifier’s level. For installations where it is preferred to keep the audio localized in a rack or common equipment location, audio level control may be extended outside the rack using an ST-VCA3.

Many installations benefit from avoiding long-term wear from audio running through a potentiometer. An ST-VCA3 with external dc control provides virtual immunity from scratchy audio. Audio/video system control units often provide 0 to 10 Vdc control outputs that can directly adjust audio levels using an ST-VCA3. The ST-VCA3 is primarily intended for line-level attenuation although a high quality utility microphone preamplifier is included in the module. If remote control of a microphone preamplifier is desired, such as a wall mounted level control for a microphone jack, the ST-VCA3 may serve as a remote controlled microphone preamplifier. The ST-VCA3 operates from a 24 Vdc ground-referenced power supply.

Wherever it is desirable to keep audio signal sources at an equipment location while providing compact, high quality remote level control, the ST-VCA3 is the ideal choice. Use an ST-VCA3 and its associated remote control individually or combine them with other RDL products as part of a complete audio/video system.

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    STICK-ON® Series Detachable Terminal Block

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    STICK-ON Mounting Plate

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    Rear rack rail mounting kit for any STICK-ON module

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


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How To Buy

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