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Dorrough electronics 40-A2 Loudness monitor

Dorrough electronics - 40-A2
Dorrough electronics - 40-A2
Dorrough electronics - 40-A2
Dorrough electronics - 40-A2
Out Of Stock
Dorrough electronics - 40-A2
Dorrough electronics - 40-A2
Dorrough electronics - 40-A2
Dorrough electronics - 40-A2
Dorrough electronics 40-A2 Loudness monitor
  • Stock: Out Of Stock
  • Code: BS18207
  • Model: 40-A2

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)


+/- 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)


2.3 lb (1.04 kg)