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Noise Control & System Protection

Guardian MK2: Overview | Specifications

Specifications

Gain
Normal operation, unit gain +0dB -1dB
Frequency Response
20Hz-30kHz ±0.5dB
Distortion
Frequency 1kHz, output level +10dBU, better than 0.01% THD
Equivalent Input noise
Better than -90dBU din audio band
Inputs
Input impedance greater than 30K.
Balanced bridging differential amplifier.
Maximum input level +22dBU.
Outputs
Electronically balanced. Source impedance 100R.
Maximum output level before clipping, into 600R load +22dBU.
Optional transformers may be ordered to provide floating output.
For unbalanced operation one side of input or output may be strapped to ground
without loss of level or deterioration in performance.
(Unbalanced input impedance greater than 15K).
Controls
All situated behind removable security front panel.
1 - priority input level into all channels.
2 - priority input level into channels 3 & 4
(allows channels 3 & 4 to be lower level than 1 & 2)
3 - Limit threshold
4 - Attenuation channels 1 & 2
5 - Attenuation channels 3 & 4
6 - Reset button. Position determines type of reset
7 - Manual test button. (Reset and test buttons may be
operated through small holes in front by suitable object).
Priority Input
Selectable mic or line with internal switch, factory set to mic.
Mic priority inputlow impedance, balanced.
Gain15dB-70dB
Line priority inputImpedance greater than 10K:
maximum input +30dBU.
Priority input socket is connected directly to priority output socket
until the unit is triggered by the control input or test button.
Then the priority input is connected into all channels as set by level controls
and disconnected from priority output socket.
Control Input
Control input voltage18V-24V AC or DC supplied as standard.
OptionSwitched pair of contacts. Close to operate. Must be isolated.
Noise Limiter
Level sense taken from channels 1 & 2.
Threshold adjustable from -10dBU to +22dBU.
If warning LED is illuminated for 6 seconds continuously the limiter will be triggered.
Limit attenuation is the same as set for priority override.
Limit will be activated for 10 seconds and has a 10 second fade back time.
Attenuation
Attenuation adjustable, maximum -45dB.
Fade back time approximately 10 seconds.
Visual Indicators
PowerGreen LED
Limit warningamber LED
Limitred LED
Priority overridered LED
Connectors
Channels 1 to 4 inputs & outputs3 pin XLR type audio connectors
Priority input & output3 pin XLR type audio connectors
Priority control input2 x 4mm binding posts
Remote indicators outputs5 pin 180° din connector
Pin 1 - Warning
Pin 2 - OVE
Pin 3 - Priority
Pin 4 - Limit
Pin 5 - NC
Remote indicators output will drive LEDs directly without series resistor
or may be used via suitable solid state relay to drive mains voltage indicators.
Power
200-240V AC (110V to order)
Mains fuse 250mA slow-blow
Captive mains lead
Finish
Front and Rear panels:Black anodised aluminium
with etched silver notation which will not rub off in use.
CaseBlack plastic-coated steel.

Dimensions
19" Rack mounting 1RU Width 482mm (19") Depth 200mm (7.9") Height 44mm (1.75")

Formula Sound reserve the right to alter specifications at any time without notice.