RDL ST-DA3 DISTRIBUTION AMPLIFIER Line level, 1x3, balanced/unbalanced

STA-1 Dual Line Amp

Separate gain controls offer up to 20dB gain. Can be used to balance unbalanced equipment or match audio levels. Impedance: input 10k bridging, output 200R balanced; frequency response: DC-25kHz ±0.25dB; dynamic range: 103dB; crosstalk: >75dB; THD: <0.009%; CMRR >70dB. Supply: dual 50mA max.

STA-1M Single Line Amp

Adjustable gain of –7/+14dB (balanced out) or –14/+7dB (unbalanced out) and separate balanced and unbalanced outputs. Fully differential input. Impedance: input 10k bridging, output 200R balanced; frequency response: 10Hz-20kHz ±0.25dB; dynamic range: 93dB; THD: <0.05%; CMRR: >50dB. Supply: dual 50mA.

STA-2A Dual High Output Line Amp

Separate gain controls offer up to 24dB gain, adjusted by 25-turn pot. Inputs bridge (5k ohms) unbalanced or balanced signals to convert to low impedance unbalanced or balanced, capable of driving 600 ohm loads. Output impedance: 150 ohms; frequency response: 10Hz-100kHz ±0.5dB; noise: –90dB ref +4dBu; headroom: 20dB above +4dBU out; CMRR: >70 dB. Supply: Single (floating), 50mA.

ST-PA2 Utility Power Amp

A single channel unbalanced amplifier with gain control and two outputs, at line and speaker level. Impedance: input 10k unbalanced line output 600R balanced speaker 8R unbalanced; frequency response: line: 20Hz–30kHz ±0.5dB, speaker 35Hz–30kHz ±1.5dB; THD: line <0.75%; dynamic range: >80dB; Max output: speaker 2W rms. Supply: single 150mA.

ST-PA6 Power Amp

Two separate inputs with common gain control and LF boost equalisation, feeding a single channel 6W 8R output. Impedance: inputs 10k balanced, output: 8R unbalanced; frequency response: 35Hz–20kHz ±1.5dB (EQ flat); equalisation: +5dB @ 60Hz, +4dB @ 100Hz, +3dB @ 120Hz; noise: <–60dB; Max output level: 6W rms. Supply: single 350mA.

ST-MA2 Muting Monitor Amplifier

Single output amplifier to drive small speakers (4–45 ohms) for talkback, conference systems. Five ground-to-operate control inputs (open collector compatible), controlled by, say, five ST-GSP1 modules, provide attenuation: One input mutes output, to avoid feedback with local mic. Two inputs for operation by two adjacent positions drop output by 6dB, to avoid feedback and colouration. Two more inputs connect to two positions located further away to reduce level by 3dB. Input: –10 dBV min for 2 Watts out, balanced or unbalanced use, 20k ohms bridging. Output power: 1.75W rms continuous, 2W max.; noise: <–80dB ref 2W out; bandwidth: 45Hz–14kHz; THD: <0.5%; CMRR: >60dB @ 100Hz. Attenuation:– Mute: >90dB @ 1kHz, two independent inputs for each of two attenuation functions of –3dB and –6dB respectively. Supply: single, ground referenced, 220mA.

ST-UBA2 Unbalanced to Balanced Amplifier

A stereo unbalanced to balanced line level converter which also provides a mono sum output. Separate preset controls are provided for input levels (gain +2 to +22dB) with two LED indicators for each channel for level setting. Input impedance: 10k ohm unbalanced line; frequency response: 20Hz-20kHz (+ or - 0.2dB); headroom 18dB above +4dBu; THD <0.02%. Supply: single 75mA.

ST-GCA3 Gain Control Amplifier

Adjustable fast or slow response automatic gain and attenuation for inputs from –45dBV to +20dBV which will hold the separate mic and line output levels to ±3dB for 40dB input range. Dual LEDs show the expansion and reduction at work. Output level: line +4dBu into 150R, mic –45dBu into 150R; frequency response (no AGC): 10Hz-20kHz ±0.75dB; noise: <–70dB; THD: <0.3%; AGC response 8s (fast) and 3s (slow) for 20dB adjustment; “on” delay: 30ms. Supply: single 40mA.

ST-GLA1 Gated Line Amplifier

Use for automatic switching of audio, as a noise gate or to construct automatic mixing systems. Open collector output for connection to other circuitry. Ref +4dBu out: Input range: –20 to +4dBu (10k ohms); headroom: >18dB; residual noise: –95db; mute threshold: –16 to –35dB. Input and output balanced or unbalanced, frequency response: 10Hz-30kHz ±0.25dB; switching time: 30mS; muting; >60dB. THD <0.2%; output 150 ohms, +4dBu, bal. Supply: single, ground referenced, 75mA.

ST-IC1 Intercom Amplifier

A single channel power amplifier with versatile mic input and dual mute switching circuit. The input accepts dynamic and condenser mics (with a separate phantom power input) or an 8 or 45 ohm speaker, and the output can be connected to any load of 4 ohms impedance or greater, delivering more than 1W rms into an 8 ohm load. The dual mute circuit allows master station override of a slave station, with a built in 15mS delay to avoid feedback. Frequency response: voice band ±2dB 300Hz–4kHz; gain range: off –70dB; Input level for 1W rms output: –60dBU (8R source), –55dBU (600R source), maximum power: 1.5W rms. Supply: Single 175mA.

ST-SH2 Stereo Headphone Amp

Separately adjustable gain controls and fully floating input stage allows this amp to be used anywhere. Impedance: Input 100k bridging, output drives 8 ohms–5k ohms; output level: 250mW into 8R, 20Vptp at 2kR; frequency response: 20Hz–40kHz ±0.25dB; noise: –100dB; THD+N: <0.005%; CMRR: >50dB at 100Hz. Supply: single 200mA

STM-1 Microphone Preamp

A single channel fixed gain (50dB) amplifier with separate balanced and unbalanced output and option for internal 24V or external phantom power supply. Operates from 12–40V DC supply. Impedance: input 150–600R balanced; 5k unbalanced, outputs 150R balanced; output level: +4dBV balanced, –10dBV unbalanced; frequency response: 50Hz–30kHz ±1.0dB; equivalent input noise: <–125dB; headroom: > 20dB (24V supply); THD: <0.05%; CMRR > 60dB. Supply: single 25mA.

STM-2 Microphone Preamp

A single channel adjustable gain (0–65dB) amplifier with two balanced outputs and option for internal 24V or external phantom power supply. Operates from 12–40V DC supply. Impedance: input 150–600R balanced, 5k unbalanced, outputs 150R balanced; frequency response: 50Hz–25kHz ±1.0dB; equivalent input noise (600R): <–130dB; headroom: >20dB (24V supply); THD: <0.05%; CMRR >60dB. Supply: single 25mA.

STM-2X Switched Mic Preamp

A single channel adjustable gain (0–65dB) amplifier with remote soft switching and balanced mic and line level outputs. Control is by either toggle or ‘push-to-talk’ switching. Ideal for ‘cough’ buttons or click-free PA switching. Impedance: input 150–600 balanced, 5k unbalanced, outputs 150R balanced; Frequency response: 50Hz–25kHz ±1dB; Residual noise: –75dB; headroom: >18dB; THD: <0.05%; CCMR: >50dB. Supply: single 30mA.

STM-3 Microphone Preamp

A high gain (0–75dB) version of STM-2 above. Specification identical to STM-2.

ST-GSP1 Gated Speech Preamp

Use to derive an automatically-switched line-level signal from a microphone, and/or a “Vox” output to trigger other modules or equipment (open collector output). Integral single-ended noise reduction. Provision is made to filter and connect phantom power. Referred to +4dBu out:– headroom: >18dB; residual noise: –80dB. Input and output balanced or unbalanced, frequency response: 15Hz–20kHz ±0.5dB; switching time: 30mS; THD: <0.03% @ 1kHz; CMRR: 45dB. Supply: single, ground referenced, 75mA.

ST-MPA24 Mic Phantom Adapter

Provides two phantom power supplies from a single DC input. The phantom voltage is adjustable up to approx 92% of incoming supply, up to P24 24Vdc as per standard IEC 61938: 2013. Protects mixer inputs from phantom power. Frequency response: 20Hz–100kHz ±0.025dB. Supply: single 35mA.

ST-MPA48 Mic Phantom Adapter

Has the same functionality as the ST-MPA24 however the Phantom power provided is 48Vdc. Supply: 12Vdc at 150mA, with 20mA load, 24Vdc at 80mA, with 20mA load.

ST-PH1 Stereo Phono Preamp

A stereo RIAA curve preamplifier with balanced outputs. Impedance: input 47k unbalanced; output 300R balanced; frequency response: RIAA curve; gain (1kHz): 40–60dB; Output level: +4dBV balanced, –2dB unbalanced; dynamic range: 93dB; crosstalk: > 65dB; THD: <0.03. Supply: dual 60mA.

ST-ACR1 Audio Controlled Relay

Identical relay to ST-LCR series, but actuated by audio line level sources. Audio specification: Input impedance: 10k bridging; operating sensitivity: –30/0dBV adjustable; release delay: 0.5-5.0s nom. Supply: single 50mA.

ST-ACR1M Audio Controlled Relay

As ST-ACR1 but mic input. Audio specification: Input impedance: 10k bridging; operating sensitivity: –60/–10dBV adjustable; release delay: 0.5-5.0s nom. Supply: single 50mA.

ST-ACR2 Audio Controlled Relay

As ST-ACR1 but extended release delay (5-50s nom.), suitable as a silence sensor.

ST-LCR1 Logic Controlled Relay

A DPDT relay with LED indicator, operated by applying a control voltage 3.5-35VDC, or a switch or open-collector closure to ground. A slave output is also available for indication or linking. Max switching current: 2A; max switching voltage: 220VDC, 250VAC; max switching power: 60W. Supply: single 50mA.

ST-LCR2 Logic Controlled Relay

As ST-LCR1 but with alternate action from pulsed inputs.

ST-VOX1 Voice Activated Relay

Audio controlled DPDT relay featuring control switching from voice signals of mic or line level. When used in intercom or talkback applications, it may be triggered directly from an unbalanced microphone. It releases very quickly, but holds on through very short pauses in syllables common to speech. These time constants allow the design of a communications system yielding comfortable two-way conversation. Multi-turn presets for sensitivity and release delay. Input impedance: mic 5k unbalanced, line 200k unbalanced. Sensitivity: mic –80dBv to –50dBv, line –45dBv to –15dBv. Activation response 5mSec release relay adjustable 70 to 260mSec. Maximum switching current: 2A; maximum switching power 60W. Supply: single 50mA.

ST-MX2 Universal Audio Mixer

A two input mic/line mixer, with mic and line level outputs. Each input is jumper selectable for mic or line level with adjustable gain (mic: -45 to -65dBu, line: -18dBV to +10dBu) . Impedance: mic input 200 ohm balanced or unbalanced, line input 20k ohm bridging balanced or unbalanced, output 150 ohm mic and line; frequency response: mic 25Hz-50kHz (+ or - 1dB), line 10Hz-30kHz (+ or - 0.25dB); headroom mic: >22dB, line: >18dBu; THD mic: <0.05%, line: <0.005%. Supply: single 60mA.

ST-MX3 Line Level Mixer

A three input balanced line mixer with separate gain controls (–14/+24dBV). Outputs can be paralleled with other modules for larger mixers. Impedance: input >30k bridging, output 400R balanced; frequency response: 10Hz–20kHz ±0.5dB; dynamic range: 102dB; THD: <0.03%; CMRR >50dB. Supply: dual 55mA.

ST-UMX3 Mic and Line Mixer

A three input switchable mic/line level output mixer with inputs switchable between mic and line level, balanced or unbalanced. Individually adjustable input levels. Impedance: mic input 600R balanced, line input 50k balanced, output: 150R balanced, 75R unbalanced; frequency response: mic ±1dB 50Hz–100kHz, line: ±0.05dB 10Hz–100kHz, gain: mic: Off to 60dB, line: Off to 21dBdB; headroom: 18dB; THD: <0.006%. Supply: Single 55mA.

STD-150 Divider/Combiner Networks

A four balanced port resistive branching network with RF protection can be used as a stereo combiner or a mono splitter. Intended for microphone lines. Input/output impedance: 150R; insertion loss: 3dB channel isolation: 3dB; maximum input signal: +22dB. Supply: passive.

STD-600 Divider/Combiner Networks

As STD-150 except 600R input/output impedance; +28dB max input level. Intended for communication lines.

STD-10k Divider/Combiner Networks

As STD-600 except 10k input/output impedance. Intended for bridging lines.

ST-OSC2A/ST-OSC2B Oscillators

These two modules each offer two, separate, fixed frequency, precision sine wave signal generators each with AGC-stabilised and user adjustable amplitude. Two outputs, each of 200 ohms output impedance, are provided for each frequency, each for connection to balanced or unbalanced circuits. Output level: “Off” to +14dBV (600 ohm load), supply input: dual 80mA. Frequencies are 1KHz plus 10kHz for ST-OSC2A and 100Hz plus 400Hz for ST-OSC2B, with distortion of 0.5% and <3% respectively. Supply: single 80mA.

ST-CX2 Line Level Crossover

A line level equaliser/crossover designed to act as a high pass channel for full range speakers to be used with ‘woofer’ speakers (below 100Hz). The equaliser has a 100Hz-30kHz pass band with 18dB/octave low frequency roll-off and a mid-band equaliser giving up to 8dB attenuation centred at 2kHz on the full range output, and a 40Hz-165Hz pass band with a low frequency equalisation of up to 10dB at 50Hz on the woofer output. Input line level: +4dB nominal, balanced or unbalanced; headroom: >18dB; THD: <0.075% (full); <0.025% (woofer). Noise <80dB. Supply: single 40mA.

ST-CX2S Sub-woofer Crossover

A line level equaliser designed to act as a sub-bass frequency channel for subwoofer speakers. The equaliser has dual bridging inputs and 22Hz-80Hz pass band and an adjustable equaliser centred at 32Hz for boosts from flat to +5.5dB. This unit is ideal where a single additional sub-woofer is to be added to stereo speaker systems, or for use with other ST-CX2 products. The CX2S is supplied factory set to match the JBL model 4645B THX approved sub-woofer. Input line level: +4dB nominal, balanced or unbalanced, bridging; headroom: >18dB; THD: <0.05%. Noise <90dB. Supply: single 30mA.

ST-SSR1 Solid State Relay

A solid state audio switch operated by grounding a trigger input to perform silent switching. Fast or slow switching. Frequency response: 30Hz-20kHz ±0.5dB; dynamic range: 98dB; THD: <0.03%; CMRR >45dB; “off” attenuation: 80dB; switching times: fast 10-20µs slow 5-35ms. Supply: single 40mA.

ST-SX4 Four input Audio Switcher

One (or non) of four unbalanced inputs at nominally –10dBV can be remotely switched to one unity gain unbalanced output by switching specified resistors to one control pair. Input impedance: 100kohms, Output impedance: 50 ohms, “off channel” attenuation: >80dB, @ 10kHz, noise and crosstalk better than 70dB below –10dBV, supply: single 40mA, headroom 23dB, frequency response: 15Hz-40kHz +/–0.5dB. Supply: single 45mA.

ST-RX2 Solid-State Switcher

Single line–level input switched between two line–level outputs by grounding (open collector compatible) control input. Use for routing or muting. Fast or soft (to avoid switching artefacts) modes. Ref +4dBu out:– headroom: >18dB; noise: <–80dB unweighted. Input and outputs balanced or unbalanced use. “Off” attenuation: >80dB; frequency response: 30Hz–20kHz ±0.5dB; THD<0.03% @ 1kHz; CMRR: >45dB @100Hz. Supply: single, ground referenced, 40mA.

ST-CL2 Compressor/Limiter

Automatically adjusting soft-knee compressor/limiter with stereo coupled terminal with fast acting peak limiting. Only input and output level presets are needed. Dual LEDs allow input adjustments to be made against compression intensity. Impedance: input 10k, output 150R balanced; frequency response: 10Hz-20kHz ±0.2dB; noise: <–78dBV; THD: <0.05% below compression, <0.15% at 6dB gain reduction; attack time: <10ms-500ms; release time: 1-500ms; ratio: 1.5:1 to 10: 1 (peak lim infinity:1); CMRR: >60dB. Supply: dual 50mA.

ST-EQ3 Three Band Equaliser

A three band line level equaliser with fixed frequencies, “clip” LED indicator and adjustable input level (off to unity). Input impedance: 100k bridging; frequency response: 20Hz–25kHz ±0.5dB (EQ flat); noise: <–76dBV; EQ cut/boost: ±12dB; centre frequencies: 80, 1k, 20kHz; THD: <0.1%; CMRR > 60dB. Supply: single 25mA.

ST-HP3 High Pass Filter

A balanced line level high pass filter with two filtered outputs (300Hz and 500Hz), the first providing 18dB/octave roll off at 225Hz, the second 18dB/octave roll off at 450Hz, designed to protect horn loudspeakers from damage by low frequency signals. Inputs and outputs may be wired unbalanced, if required. Frequency response: ±0.5dB 300Hz-30kHz (300Hz out), ±1.0dB 500Hz-30kHz (500Hz out); THD and noise: <0.01%; insertion loss: <2dB; Headroom: >18dB. Supply: single 30mA.

ST-FS6 Ferrite Suppressors

Six single ferrite suppressors for the reduction of RF signals. These may be used to suppress RF pick up in signal or screen wires, depending on the situation. Two ground terminals are also provided. Attenuation >10dB at 10MHz, >25dB at 200MHz.

STP-1 Universal Attenuator

A dual variable attenuator for balanced and unbalanced circuits. Attenuation: 10k balanced/unbalanced: 1-85dB, 600R balanced: 5-35dB; max input signals: 10k +33dBV, 600R +27dBV. Supply: passive.

ST-NG1 Noise Generator

A white or pink noise generator with separately adjustable mic and line level balanced outputs. The truly random noise source occupies the full bandwidth 20Hz-20kHz with amplitude limiting circuitry to control peak excursions while maintaining random variations of at least 20dB. Ideal for system alignment and measurement and noise masking. Supply: single 30mA.

ST-RG1 Ramp Generator

A ramp generator with 0-10 VDC output. Two control ports, “up” and “down” with tally LED drives to show status. Normally open switches applied to the control ports ramp the output up or down, leaving the output stable in the last set conditions when released. When used in conjunction with RLC1/RLC2 and ST-VCA1 a complete remote volume control system can be put together. LED O/P current 3mA; Ramp O/P 0 to 10V nominal; Ramp time 5 sec max; supply: Single 40mA.

RLC1

Control assembly for use with ST-RG1. Features membrane style up/down buttons and red and green status LEDs. Uses interconnect cable telecom 3 pair (not included). 33mm wide, 6mm high.
Available mounted on a UK standard 1 gang BS4662 type plastic plate (58-448), or as a module for user mounting into other wall plates and control panels (58-449).

ST-TC1 Telephone System Coupler

Primarily intended to be connected to an on-site telephone system switching unit. Connections from the ST-TC1 go into the switching unit as if it were a normal extension line (viz. in place of an extension telephone). When the line the ST-TC1 is connected to is seized, a relay contact closure is provided which can be used to control a variety of equipment, such as paging priority access or channel open, or radio “PTT”. The closure is maintained as long as the line is selected. A 600R transformer isolated audio feed is available for audio input/output. Switching contacts are double pole double throw, rated 60 watts 125VA. Max. switching voltage 220VDC, 250VAC, 2A. Supply: 50mA single.

ST-VP1 Voice-over/Paging Module

A line-level unity-gain two-input “programmed fade” mixing amplifier suited to paging or studio applications. “Music” input, normally present at output, fades down and “Voice” input is mixed in when control input is grounded. Separate control input provides soft switching between inputs. Music fade adjustments: rate 0.2 to 1.3 sec, depth 3 to 40dB; voice channel attenuation when muted: >70dB; frequency response +0.25dB: voice 30Hz-20kHz, music 10Hz–20kHz; THD: <0.1%; dynamic range: >93dB; Supply: single 45mA.

ST-VP2 Automatic ducking module

The ST-VP2 offers fully automatic voice-over mixing, useful also for noiseless paging interrupts. It features adjustable fade depth 0dB to 25dB (plus fully off), and has adjustable recovery rate (2sec - 4sec), together with AGC on the music input (18dB range, 6dB compression at normal input level, 25msec attack time, 2.5sec release. The music and voice inputs are both line level, and an adjustable threshold gate mutes the voice channel between paging announcements. LED’s are provided to show the correct operating level for each input, to aid set-up. 24-33VDC 35mA.

ST-PD5U Power Supply Distributor

This unit provides five individually de-coupled and diode isolated outputs from a single DC input. Typically it would be used to provide the supply voltage to five individual Stick-On modules from a single, possibly remote, source. One ST-PD5U should be used per power rail employed, ie: one to feed single-rail devices, two to feed dual-rail devices. Avoid mixed use! Input voltage 0-36VDC, output voltage typically 0.7VDC less than input.