Precision Audio and AV Interface Products

Radio Design Labs

ST-VCA3 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
  • Overview
  • Specifications
  • Related Products
  • Accessories
  • Downloads
  • How to Buy
  • Product Series
  • Dimensions

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 the rack, audio controls are extended outside the rack from the ST-VCA3. Many installations benefit from avoiding long-term potentiometer wear from audio running through the 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 control audio levels using an ST-VCA3. The ST-VCA3 is primarily intended for line-level attenuation; 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.

Applications

Inputs (2):
Mic: 200 Ω balanced; 5 kΩ unbalanced
Line: 30 kΩ bal. bridging or unbalanced
Input Levels (for +4 dBu output):
Mic: −44 dBu to −60 dBu (150 Ω source)
Line: -18 dBu (-20 dBV) to +4 dBu
Output Signal (normal rated):
+4 dBu, 150 Ω balanced
Headroom:
18 dB
THD+N:
Mic: < 0.05%; Line: <0.025% (unity gain);
0.025% typical at 15 dB attenuation
Frequency Response:
Mic: 30 Hz to 20 kHz (±1 dB)
Line: 10 Hz to 20 kHz (±0.1 dB)
Noise:
Mic: < -71 dB below +4 dBu output (150 Ω source; 50 dB gain)
Line: <-78 dB below +4 dBu output (maximum gain)
CMRR:
Mic: > 60 dB; Line: > 60 dB, (50 Hz to 120 Hz)
Control Input:
0 to 10 Vdc or 0 to 10 kΩ Linear
Attenuation Range:
0 to 90 dB (>90 dB at 0 Vdc control)
Ambient Operating Environment:
0° C to 55° C
Power Requirement:
GROUND-REFERENCED, 24 Vdc @ 50 mA
Dimensions:
Height: 0.7 in. (1.7 cm), Width: 3 in. (7.6 cm), Depth: 1.6 in. (3.9 cm)
Package Type:
Cardboard Box
Package Dimensions:
2 x 2 x 4 in.
Shipping Weight:
0.2 lbs.
WEEE weight:
0.145 lbs.
Tariff code:
8543.70.9860

Documents:
Format
PDF
CAD Files:
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High Res Images:
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Declaration of Conformity:
Format
PDF
A&E Specifications:
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STICK-ON SERIES

STICK-ONs are the original application-specific modules for the A/V, recording and broadcast industries. Module functions include signal detection, switching, pre-amplification, format conversion, line driving, power amplification, mixing, distribution, gain control, equalization, routing and more. Each STICK-ON is an ultra-compact module engineered to provide higher performance and longer life than other industry products. STICK-ON modules are solid encapsulated hybrid circuits in durable industrial black plastic enclosures (1.55", 3.94 cm x 3", 7.62 cm x 0.65", 1.65 cm) with clear bold white lettering for the terminal block connections, recessed trimming controls and switches.

Since RDL first originated application-specific modules, STICK-ONs have led the industry in economical, high-performance and cost-effective long life solutions in system designs. Multiple STICK-ON modules can be interconnected to form all or part of an A/V system. A single STICK-ON module may be mounted right where its function is needed, often to add an input, output, or gain adjustment to existing equipment. STICK-ON modules allow customizing an A/V system to precisely match users’ needs. Adding STICK-ONs to an existing system can extend system life by adding updated features, resulting in considerable cost savings. A complete range of backboard and rack mounting options is available for systems comprised of multiple STICK-ON modules.

The technology used in STICK-ON modules has been regularly updated over the years to insure industry-leading performance. Functions and features provided by STICK-ONs, since their introduction, are still available today. This continuity in product offering and support makes STICK-ON modules the preferred long-term resource for system design solutions. STICK-ON SERIES modules are designed and manufactured in the U.S.A.

ST-VCA3 ST-VCA3