Dorrough electronics 40-A2 Loudness monitor
The Dorrough 40-A2 is a professional analog loudness meter, designed for modern stereo recording and broadcast requirements, and offering simultaneous average and peak program display, with separate ballistics and lightning-fast response. This meter is equipped with a 40-LED bar graph, showing 1dB of resolution per LED, and 14dB of headroom.
Rack or console mounted Analog Loudness Meter with dual dedicated ballistics for simultaneous peak and average readout
Microchip processor with accuracy of oscilloscope, ultra-fast response time of 600ms average, virtually instantaneous peak for seamless continuous display of peak/average relationship
Individual left and right XLR inputs for stereo mixing applications, +4 dB factory-calibrated
Display with 40 LED's providing 1dB resolution per LED
Proprietary "A" scale with 14dB of headroom
XLR, 6 DIP switches for function assignments, mini 8-pin DIN port out for access to alarm relays, meter mode functions, and peak hold modes, standard with unit
Technical Details |
Dorrough electronics 40-A2 Specs Input Impedance | 20 kOhm balanced 10 kOhm single-ended, +/- 2% | Common Mode Rejection Ratio | 80 dB at 60 Hz 60 dB at 20 kHz (balanced mode) | Input Sensitivity | -10 dB for full-scale display | Maximum Input Level | +24 dB before clipping | Signal Path Bandwidth | 10 Hz - 25 kHz, +/- .25 dB | Signal Path Distortion | >1% THD at 1 kHz, +24 dB input | Sum Error | >0.1 dB at 1 kHz | Difference Error | >0.1 dB at 1 kHz | Display Resolution | 40 LEDs, 1 dB/LED | Step Size Error | +/- 0.25 dB | Absolute Error | +/- 0.25 dB (Full Scale -39 dBu) | Drift | +/- 0.25 dB | Average Time Constant | 600 mS, +/- 6% | Peak Acquisition Period | 10 uS, to full-scale, sine input 25kHz | Peak Attack Period | Virtually Instantaneous | Peak Decay Period | 180 mS, from full-scale to all LEDs off | Display Update Rate | Approximately 10 mS | Display Duty Cycle | Display Time, AVERAGE, PEAK HOLD - 75% Display Time, PEAK - 100% | Power Supply Input Range | 117/237 VAC RMS, -20% to +10%, 50-60 Hz | Calibration Controls | None needed | User Controls | Left/Right input sensitivity Option DIP Switch: A) Peak Auto [ON] B) Difference Mode [ON/OFF] C) Over Level Alarm [ENABLE] D) Under Level Alarm [ENABLE] E) Auto ARMP | User Port | DB-9 Connector: A) Alarm relay closure contacts,1 form C, 1A, 30V AC or DC B) Mode control switch (user supplied) C) PEAK function switch (user supplied) | Dimensions (WxDxH) | 8.5 x 6.5 x 2.8" (215.9 x 165.1 x 71.1mm) | Weight | 2.3 lb (1.04 kg) |
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