Description
OXMOOR DIGITAL CONTROL ATTENUATOR
DCA-2T Digital Control Attenuator
This system provides remote control of audio system levels, using digital control pulse techniques. The 1U rackmount control unit is located with the rest of the system equipment to keep audio cable as short as possible. A total of eight remote controls (such as the RC-16 rotary control) may be used with each DCA-2T in the system. US style 4 or 6 core telephone cable, using the RJ11 or RJ12 crimp telephone connectors, are required to connect the remote controls to the DCA-2T unit. Each remote control display the current system volume level, and each can adjust it in precise 1.5dB steps. Remotes can be switched out of circuit or even disconnected without affecting levels.
Each DCA-2T has two channels which can be controlled individually (with high isolation between them), or ganged into a stereo pair using rear panel looping connectors. If channels are ganged, they track each other to within 0.25dB.
A rear-panel preset adjustment sets the default attenuation, so systems behave predictably at switch-on. During operation, an external make contact will return the system to this level. Similarly, a priority adjustment temporarily changes the audio level (or mutes it completely) as long as an external contact is made. This enables external interruptions, such as paging calls, to always be at the same level, regardless of the system level at the time.
Inputs are electronically balanced, outputs transformer balanced. Front panel preset gain controls allow the maximum system level to be set in the range –15dB to +15dB (relative to input level).
Technical Specification:
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Frequency response: | 20Hz to 20kHz: +0, –0.3dB, –3dB points ref 1kHz, 4Hz, 60kHz (@ +4dBm, max gain) |
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Hum and noise: | Unweighted –80dB ( 0dBm output @ unity gain) |
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Crosstalk: | 20Hz to 20kHz: –90dB |
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Inputs: | Electronically balanced (RF suppressed), 80k ohm Maximum input level +20dBu |
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| Common mode rejection ratio 50dB at 1kHz |
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Outputs: | Source impedance 150 ohms transformer balanced. Load impedance 600 (min). Maximum output level @ rated THD. Terminated w/600 ohms +18dBm |
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Digital attenuator: | Control range 0 to –43.5dB in 29 steps plus a 90dB full attenuation (“kill”) step. |
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| Tracking accuracy (channel to channel) within ±0.1dB throughout attenuator range. |
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| Preset and priority range: 15 steps (of 3dB each) plus “kill’ |
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Control loop: | Maximum number controls per channel 4. |
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| Maximum cable length to furthest remote 600m |
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Contact requirement for | Single pole switch or open collector transistor |
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Preset and priority | (128mA capacity) dry closure to logic ground. |
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functions: | Wiring scheme – daisy-chained connection via looping jack on each DCA-2T channel and each remote control Cable connectors – 4 wire modular telephone type (RJ11/RJ12) or 6-wire for remote preset or priority function |
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Mains power: | 100–130V AC/200–240V AC |
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Dimensions: | 44(h) × 482(w) × 183(d) mm. Weight 3.1kg |
Full data sheets are available on request. Manufactured in the USA by Oxmoor Corporation. Oxmoor ™ . DCA ™ , RC-16 ™ and Virtual Pointer ™ are all trademarks of Oxmoor Corporation.