Sound Technology

ST-ACR2

Line-Level Audio Controlled Relay - 5 to 50 s delay

The ST-ACR2 is an Audio Controlled Relay in the STICK-ON® series. These products are designed for quick, convenient installation, and reliable operation in a variety of control applications. The ST-ACR2 is designed to switch on line level sources.

Two multiturn trimmers are provided. The SENS potentiometer adjusts the audio input sensitivity. A threshold LED facilitates accurate adjustment. The module can be set to trigger on signals between -30 dBu and 0 dBu. The DELAY control sets the time required for the relay to release when the audio drops below the threshold.

The delay adjustment range for the ST-ACR2 is from 5 seconds to 50 seconds.

Audio Input10 kΩ balanced bridging
Input ConnectionsMay be connected balanced or unbalanced
Control OutputOpen-collector @ 25 mA suitable to drive indicators or slave LCR relay
IndicatorsAudio threshold LED (for setting sensitivity)
Retrigger Delay250 ms
ContactsDouble-pole-double-throw
Max. Switching Power60 W, 125 VA
Max. Switching Voltage220 Vdc, 250 Vac
Max. Switching Current2 A
Activation Response Time25 ms
Input Sensitivity-30 dBu to 0 dBu (adjustable)
Relay Release Delay5 sec. to 50 sec. nominal (adjustable)
Ambient Operating Environment0° C to 55° C
Power RequirementGROUND-REFERENCED, 24 Vdc @ 50 mA* * Assumes 20 mA max load at SLAVE output
DimensionsHeight: 0.7 in. (1.7 cm), Width: 3 in. (7.6 cm), Depth: 1.6 in. (3.9 cm)
Package TypeCardboard Box
Tariff code8543.70.9860
WEEE weight0.15 lbs.
Shipping Weight0.2 lbs.
Package Dimensions2 x 2 x 4 in.
  • Switching Controlled by Audio Signal
  • Sensing of Line-Level Signal
  • Silence Sensing
  • DPDT Switching Contacts
  • Open-Collector SLAVE Output