Dorrough 280 - User Manual

Digital Loudness Meters
Model 280 and 380
Technical Instruction Manual
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U.S.A. 380-D
-57 -54 -51 -48 -45 -42 -39 -36 -33 -30 -29 -28 -27 -26 -25 -24 -23 -22 -21 -20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0
-57 -54 -51 -48 -45 -42 -39 -36 -33 -30 -29 -28 -27 -26 -25 -24 -23 -22 -21 -20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0
MODEL 280-E U.S.A.
-39 -38 -37 -36 -35 -34 -33 -32 -31 -30 -29 -28 -27 -26 -25 -24 -23 -22 -21 -20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0
-39 -38 -37 -36 -35 -34 -33 -32 -31 -30 -29 -28 -27 -26 -25 -24 -23 -22 -21 -20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0
MODEL 280-D U.S.A.
Model 280-D
Model 280-E

Summary

Introduction

Loudness Monitoring

Discusses historical audio monitoring standards (VU, PPM) and their limitations.

Digital Audio and the Dorrough Loudness Meter

Explains the AES/EBU digital audio interface standard and its monitoring implications.

The Dorrough 280 and 380

Introduces Dorrough DLM models 280/380 and their mounting options.

Specifications

Details technical specs: compatibility, signal interface, and scale options.

Installation

General Installation Information

Provides general DLM installation guidance and warranty details.

Unpacking DLMs

Instructions for careful unpacking of Dorrough Digital Loudness Meters.

Mounting Models 280 and 380

Describes mounting procedures for Model 280 (horizontal) and Model 380 (vertical).

Electrical Connections

Details DLM electrical connections: signal, peak hold selection, and DC power.

Initial Setup and Verification

Outlines DLM initial setup steps, including applying a tone for verification.

Operation

General Operation

Explains automatic DLM operation and format detection capabilities.

Digital Headroom and Crash Point

Discusses overrange indication, crash point, and monitoring implications.

Peak Hold Switch Functions

Details the three peak hold functions (normal, indefinite, disabled) and their selection.

Maintenance

General Maintenance

States DLMs require minimal maintenance, mainly cleaning and jumper settings.

Cover Removal Procedure

Provides instructions for removing the unit's cover for internal access.

Jumper Settings

Explains functions and settings of DLM circuit board jumpers.

Lamp Replacement

Describes the procedure for replacing scale illumination lamps.

Return Procedures

Outlines steps for returning the unit for service, including RMA acquisition.

Dorrough 280 Specifications

General

Brand	Dorrough
Model	280
Category	Multimeter
Language	English