ST-GLA1 Gated Line Amplifier / Noise Gate
The gated line amplifier / noise gate unit shall be an RDL ST-GLA1. The unit shall provide one balanced line-level audio input. The unit shall detect a valid audio signal on the input to activate the line-level audio output an open-collector output terminal and a 24 Vdc power output terminal.

The input shall have an input impedance no less than 10 kOhms. The input signal range shall be -15 dBV to +4 dBu for an output of +4 dBu.

Two continuously adjustable multi-turn trimming controls shall be provided. One trimmer shall be provided to set the sensitivity of the audio detector circuit to a value from 16 dB to 35 dB below +4 dBu. A corresponding LED indicator shall be provided to indicate the detection of audio to facilitate proper input sensitivity adjustment. The sensitivity adjustment shall be labeled GATE. One trimmer shall be provided to set the gain of the input preamplifier stage. The gain control shall be labeled LEVEL. The unit shall provide two LED indicators, one for the correct level and one indicating when the output is gated on.

The signal detection circuit shall activate within 30 ms of audio detection from input signals within the bandwidth of 20 Hz to 5 kHz. The release delay shall be fixed at 2 seconds. The unit shall provide a terminal labeled DELAY+ permitting connection of an external timing capacitor to extend the release delay to any value up to 60 seconds. The open collector SLAVE output shall be capable of sinking 50 mA.

The unit shall provide audio frequency response of 10 Hz to 30 kHz (± 0.25 dB) with total harmonic distortion and noise <0.2% and a noise floor exceeding 95 dB below an output level of +4 dBu with the unit output gated off.  The input signal shall be attenuated more than 60 dB when the output is gated off. The unit shall provide output headroom of no less than 16 dB above an output level of +4 dBu.

When the output is gated on, the unit shall provide dynamic noise reduction circuitry to reduce the noise floor. Audio attenuation shall be adjusted using solid-state circuitry.  Muting shall be accomplished with solid-state soft switching techniques without audible clicks or edge transitions.

The unit shall provide one line-level balanced audio output at a nominal rated output level of +4 dBu with an output impedance of 150 O. The output circuit shall be configured to produce an unbalanced output of proper phase between the positive output leg and ground. 

The unit shall be constructed in an electrically non-conductive, thermally conductive enclosure. Internal circuitry shall be protected from moisture and vibration using a thermally conductive compound that permanently secures the circuitry within the enclosure.

The face of the unit shall provide graphical labels identifying wiring connections and operating controls. Indicators and controls shall be oriented toward the front edge of the unit.

Connection to external wiring shall be provided using a fixed terminal block on the edge of the unit. The terminal block shall accept wiring gauges from 14 to 22 and shall include a positive electrically conductive mechanism to prevent wire abrasion by the terminal screws.

The unit shall measure 3” (7.6 cm) x 1.6” (4 cm) x 0.7” (1.7 cm) and be compatible with all RDL STICK-ON mounting accessories. The unit shall be supplied with a two part re-closable polypropylene fastener system equipped with a rubber adhesive that bonds to low surface energy materials.

Power requirements shall be 24 Vdc ground-referenced with a maximum current not exceeding 75 mA with no load connected to the open-collector slave output terminal. The unit shall utilize an external power supply. The unit shall provide a loop output terminal for the 24 Vdc power input. The unit shall be engineered, assembled and tested in the U.S.A. and be specified for continuous duty in professional installed systems. The unit shall be specified for operation in an ambient temperature between 0 and 55 degrees C. The unit shall comply with relevant EMC requirements and shall bear the CE marking.

The unit shall be an RDL ST-GLA1.