User manual

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AMP1-DA User Manual P/N 821530 Rev-C

Please refer to Figure-2a on the following page to familiarize yourself with the front panel features of the AMP1-DA unit. The following

sections describe these functions and are referenced, by number, to Figure-2a.

Section 2: Operation

Front Panel Features

Speakers

The AMP1-DA internal speaker system is comprised of two mid-range tweeter speakers (left and right) and two woofer speakers

(left and right). The two mid-range speakers reproduce, in stereo, only the mid and high frequencies, while the two woofer speakers

monorally reproduce the low frequencies. See page 14 for more information about the speaker configuration of the AMP1 Series.

Volume Control

This controls the loudness of the audio reproduced by the internal speakers or connected headphone. Clock-wise rotation of this

control increases the loudness of the monitored audio.

Headphone Jack

Select the headphone audio sources as you would for the internal speakers. When you plug in headphones, the internal speakers will

mute. This jack accepts a standard "mini" stereo (ring/tip/sleeve) plug.

Power Indication LED

This LED glows green to indicate the unit is connected to operational mains power.

Phase Indication LEDs

These three LEDs offer instant visual verification of phase (polarity) conditions in the pair of channels selected for monitoring in the

Left/Right channel speakers. The two smaller LEDs, labeled

ΦΦ

Φ+ and

ΦΦ

Φ- (above and below), show instantaneous phase relationships

in the signal, while the larger center LED, labeled AVG, indicates the average phase condition.

The small top

ΦΦ

Φ+ LED glows (or blinks) GREEN when signals are in-phase. The small bottom

ΦΦ

Φ- LED glows (or blinks) AMBER

for out-of-phase signals. The larger AVG LED indicates the average phase condition by glowing GREEN for in-phase conditions,

or RED for out-of-phase conditions.

In general, it is sufficient to regard the AVG LED (average phase condition) as adequate for proper phase monitoring. While it is

normal for stereo signals to contain some intermittant instantaneous out-of-phase and in-phase conditions (small LEDs), a steady

red glow of the larger LED almost always indicates an out-of-phase alarm condition.

Audio Level Meters

Audio levels for the selected input sources are displayed via these two 26-segment tri-color (GREEN, AMBER, RED) LED

bargraph display level meters.

These two bargraph displays feature an Auto-Calibration feature and are user adjustable for Display Mode and Reference Level

via a rear panel DIP module (Item F, page 12). Peak Hold, PPM Ballistics, and Alternative Scales can be set via an internal

DIP module. See pages 18 and 19 for more information regarding these DIP switch module locations and settings.

AES/EBU Signal Status Indication LED

This LED indicates the status of the currently selected AES digital signal (AES1 or AES2) regardless of any other monitor

selection settings.

This LED glows GREEN as long as a valid AES digital datastream is being received. It will glow RED to indicate errors in the

reception of the AES signal. There are two DIP switch selectable modes of fault detection that will create a RED LED error

indication. Please see Item B, page 10 for more information about this setting.

An additional feature of the AES signal error detection is the ability to mute the audio when errors are detected in the AES signal. To

enable this feature, a jumper is placed at H12 of the 919117 PCB. See page 21 for location of H12 on the 919117 PCB.

Digital Source Select Switch

This switch selects between the two AES/EBU IN (IN1 or IN2) source inputs (Item C, page 10). Note that for the selected AES

source to be monitored, the Analog/Digital Source Select Switch (Item 9) must be set to DIGITAL.

Analog/Digital Source Select Switch

When this toggle switch is set to ANALOG, the unit will monitor the analog input signals from the ANALOG IN XLR connectors

on the rear panel (Item G, page 14). When this toggle switch is set to DIGITAL, the unit will monitor the selected AES/EBU IN

input (IN1 or IN2) on the rear panel (Item C, page 10).

Balance Control

This pans the volume balance between the left and right speakers. See page 14 for more information about the balance control

characteristrics of the AMP1 Series.

Bargraph Brightness Adjust

This control is recessed into the front panel and can be accessed using a small flathead screwdriver. Turning the trim pot clockwise

will simultaneously increase the relative brightness of the LED segments in both bargraphs.